Exhibit 10.27



                 FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT
                 ----------------------------------------------

         This FIRST AMENDMENT TO PURCHASE AND SALE AGREEMENT ("First
Amendment"), dated as of December 14, 2005, is made between SQUARE 711
DEVELOPER, LLC, a Delaware limited liability company ("Seller"), and WALTON
ACQUISITION HOLDINGS V, L.L.C., a Delaware limited liability company ("Buyer").

                                    RECITALS
                                    --------

         WHEREAS, Seller and Buyer have entered into that certain Purchase and
Sale Agreement dated as of November 14, 2005 (the "Original Agreement") for the
purchase and sale of certain real property located in Washington, D.C., and
known as Square 711, Lot 160, as more particularly described in the Original
Agreement; and

         WHEREAS, Seller and Buyer desire to amend the Original Agreement as
provided herein.

                                    AGREEMENT
                                    ---------

         NOW, THEREFORE, for good and valuable consideration, the adequacy and
receipt of which is hereby acknowledged, the parties hereby agree as follows:

         1. Defined Terms. Capitalized terms that are not otherwise defined in
this First Amendment shall have the same meaning ascribed thereto in the
Original Agreement. The Original Agreement, as amended by this First Amendment,
is referred to in this First Amendment as the "Purchase Agreement."

         2. Purchase Price. Notwithstanding any provision of the Original
Agreement to the contrary, including, but not limited to, Section 1.01(a)
thereof, the term "Purchase Price" shall mean the sum of One Hundred Twenty-One
Million Eight Hundred Eighty-Five Thousand and No/100 Dollars ($121,885,000.00).

         3. Density Bonus Covenant. Section 1.01(b) of the Original Agreement is
hereby deleted in the entirety and all references to the Density Bonus Covenant
are hereby stricken from the Original Agreement.

         4. Deposit. Upon Buyer's execution and delivery of this First Amendment
to Seller, the Initial Deposit shall be non-refundable to Buyer (except as
otherwise provided in the Original Agreement, including, but not limited to,
Sections 2.04 and 7.01 thereof), and Buyer shall have no further right to
terminate the Purchase Agreement under Section 2.02 thereof. Notwithstanding the
provisions of Section 1.02(a) to the contrary, Buyer shall have until 3:00 p.m.
(Washington, DC time) on December 15, 2005, to deposit the Second Deposit with
the Escrow Agent.

         5. Pro Forma Title Policy. The pro forma title policy attached hereto
as Exhibit A is the pro forma for purposes of the closing condition set forth in
Section 3.02(iii) of the Original Agreement. Buyer has approved the pro forma
title policy attached hereto as Exhibit A, and Buyer has also approved the
updated survey of the Property prepared by Vika Incorporated.


         6. Assignment of Right of First Refusal. At Closing, Seller shall
assign to Buyer its right, title and interest in the "Right of First Refusal"
(as hereinafter defined) pursuant to the form of assignment attached hereto as
Exhibit B (the "Assignment of Right of First Refusal"). "Right of First Refusal"
means that certain right of first refusal to purchase, lease, or otherwise
obtain any interest in or portion of the real property (the "Adjacent Property")
conveyed by First & M Street Investing Company, LLC, a Delaware limited
liability company, to the Washington Metropolitan Area Transit Authority
("WMATA") pursuant to that certain Deed of Gift, dated July 16, 2003, which
right may be exercised if WMATA desires to sell, lease, assign, transfer or
otherwise grant, convey or dispose of the same, including, without limitation,
any air rights or rights to develop improvements in the air space above the
Adjacent Property.

         7. Assignment to Land Trust. Without limitation on the provisions of
Section 9.01 of the Original Agreement, Buyer shall be permitted to assign its
rights as buyer under the Purchase Agreement to a land trust organized under the
laws of the District of Columbia which is beneficially owned by an entity
controlled by or under common control with Walton Street Capital, LLC and an
entity controlled by or under common control with StonebridgeCarras, LLC.
Notwithstanding such assignment, Walton Acquisition Holdings V, L.L.C. shall
remain liable for all obligations of Buyer under the Purchase Agreement.

         8. Extension of Closing Date. The Closing Date is hereby extended to
February 15, 2006. Time is of the essence as to such Closing Date.

         9. Davis Agreement.

         a.       Seller shall request that Walsh/Davis Joint Venture Buyer and
                  its lender to be added as additional insureds under the
                  insurance carried in connection with the Davis Agreement as of
                  the Closing. Seller's inability to cause such change to be
                  made to Walsh/Davis Joint Venture's policy shall not be a
                  default under the Purchase Agreement nor shall the
                  implementation of such change be a condition to closing for
                  Buyer.

         b.       The term "Davis Agreement" as used in the Purchase Agreement
                  shall be revised to mean "collectively, (a) that certain
                  letter dated August 2, 2004 from Walsh/Davis Joint Venture to
                  Seller; and (b) that certain letter dated April 6, 2005 from
                  Seller to Walsh/Davis Joint Venture and countersigned by
                  Walsh/Davis Joint Venture on April 25, 2005."

         10. Additional Closing Deliveries. In addition to the deliveries
required under Section 5.02 of the Original Agreement, at Closing Seller shall
also be required to deliver the following documents: (a) a notice to WMATA that
Buyer will become the successor owner of the Property and that all future
notices should be delivered to Buyer, (b) a notice to CSX Realty Development,
LLC that Seller's interest in the CSX Environmental Agreements has been assigned
to Buyer, and (c) the Assignment of Right of First Refusal, duly executed and
acknowledged by Seller. In addition to the deliveries required under Section
5.03 of the Original Agreement, at Closing Buyer shall also be required to
deliver the Assignment of Right of First Refusal, duly executed and acknowledged
by Buyer.

                                       2

         11. Work Plan. The last sentence of Section 2.05 of the Original
Agreement is hereby deleted and replaced with the following sentence: "At
Closing, Seller shall assign to Buyer all of Seller's rights accruing from and
after the Closing under the CSX Environmental Agreements, and Buyer shall
assume, pursuant to the Assignment of Environmental Agreements (as defined
below), all of Seller's obligations, if any, under the CSX Environmental
Agreements." The definition of "Assignment of Environmental Agreements" is
hereby changed to "an assignment and assumption of the CSX Environmental
Agreements in the form attached hereto as Exhibit F." All references to "that
certain letter dated December 13, 1999 from Theodore J. Gordon, Chief Deputy for
Public Health Assurance, to CSX Real Property" in the Assignment of
Environmental Agreements are hereby stricken.

         12. Reaffirmation. The terms of this First Amendment shall govern and
control over any conflicting provisions in the Original Agreement. Except in the
case of such conflicts and as expressly amended by this First Amendment, the
terms and provisions of the Original Agreement shall remain unchanged and in
full force and effect.

         13. Counterparts. This First Amendment may be executed in one or more
counterparts, all of which shall be considered one and the same agreement, and
such counterparts may be exchanged by facsimile or electronic transmission.


                    [SIGNATURES APPEAR ON THE FOLLOWING PAGE]


















                                       3

          IN WITNESS WHEREOF, the parties hereto have executed this First
Amendment as of the date set forth above.


                           SELLER:
                           -------

                           SQUARE 711 DEVELOPER, LLC,
                           A DELAWARE LIMITED LIABILITY COMPANY


                           By:
                               -----------------------------------------------
                               Joseph M. O'Connor
                               Executive Manager



                           BUYER:
                           ------

                           WALTON ACQUISITION HOLDINGS V, L.L.C.,
                           A DELAWARE LIMITED LIABILITY COMPANY

                           By: Walton Street Real Estate Fund V, L.P.,
                               a Delaware limited partnership
                               its Managing Member

                               By: Walton Street Managers V, L.P.,
                                   a Delaware limited partnership
                                   its General Partner

                                   By: WSC Managers V, Inc.,
                                       a Delaware corporation
                                       its General Partner

                                       By:
                                           -----------------------------------
                                           Name:
                                           Title:




                                       4

                                    EXHIBIT A
                                    ---------

                             PRO FORMA TITLE POLICY
                             ----------------------










                                    EXHIBIT B
                                    ---------

                  FORM OF ASSIGNMENT OF RIGHT OF FIRST REFUSAL
                  --------------------------------------------


         THIS ASSIGNMENT OF RIGHT OF FIRST REFUSAL (the "ASSIGNMENT") is made
and entered into as of the ___ day of _____________, 2006, by and between SQUARE
711 DEVELOPER, LLC, a Delaware limited liability company ("Assignor") and
________________________, a Delaware limited liability company ("ASSIGNEE").

                                   WITNESSETH:

         A. Assignor, as seller, and Walton Acquisition Holdings V, L.L.C., a
Delaware limited liability company ("ORIGINAL BUYER"), the predecessor in
interest to Assignee, as purchaser, have entered into that certain Purchase and
Sale Agreement dated November 14, 2005 (as amended and modified, the "PURCHASE
AGREEMENT") whereby Assignor has agreed to sell, and Original Buyer agreed to
purchase, certain real property in the District of Columbia more particularly
described in the Purchase Agreement (the "PROPERTY").

         B. First & M Street Investing Company, LLC, a Delaware limited
liability company ("PRIOR OWNER"), donated real property adjacent to the
Property (the "ADJACENT PROPERTY") to the Washington Metropolitan Area Transit
Authority ("WMATA"), which WMATA has used for part of the development of a new
Metro Station. In connection therewith, (i) Prior Owner and WMATA entered into a
certain letter agreement between Prior Owner and WMATA executed by Prior Owner
on July 16, 2003 and by WMATA on July 29, 2003, a copy of which is attached
hereto as Exhibit A (the "LETTER AGREEMENT"), (ii) Prior Owner and WMATA entered
into a certain Washington Metropolitan Area Transit Authority Lease for Real
Property (the "LEASE") between Prior Owner, as lessor, and WMATA, as lessee,
dated July 16, 2003, and (iii) in the Deed of Gift from Prior Owner to WMATA,
dated July 16, 2003, attached hereto as Exhibit B, Prior Owner reserved a right
of first refusal to purchase, lease, or otherwise obtain any interest in or
portion of the Adjacent Property in the event WMATA desires to sell, lease,
assign, transfer or otherwise grant, convey or dispose of the same, including,
without limitation, any air rights or rights to develop improvements in the air
space above the Adjacent Property (the "RIGHT OF FIRST REFUSAL").

         C. Pursuant to that certain Assignment of Lease and Other Rights
between Prior Owner and Assignor, dated as of September 15, 2003, and attached
hereto as Exhibit C, Prior Owner assigned to Assignor certain rights of Prior
Owner under the Letter Agreement, the Lease and the Right of First Refusal.

         D. In connection with the Purchase Agreement, Assignor has agreed to
assign, transfer and convey to Assignee, and Assignee has agreed to take and
accept the right, title and interest of Assignor under the Right of First
Refusal.

                                   AGREEMENT:

         NOW, THEREFORE, in consideration of the mutual covenants and agreements
herein set forth and other good and valuable consideration, the receipt of
sufficiency of which are acknowledged hereby, the parties agree as follows:


         1. Assignor hereby assigns, transfers and sets over unto Assignee all
of Assignor's right, title and interest under the Right of First Refusal
accruing from and after the date hereof.

         2. Assignee hereby accepts such assignment and assumes all of
Assignor's obligations under the Right of First Refusal accruing from and after
the date hereof.

         3. This Assignment shall be construed under the laws of the District of
Columbia.

         4. This Assignment is made without representation or warranty from
Assignor, except as may be specifically set forth in the Purchase Agreement, and
subject to all conditions and limitations set forth therein as to Assignor's
liability, and as provided below in this Section 4, Assignor represents and
warrants to Assignee that Assignor has not previously assigned, encumbered or
otherwise transferred its rights under the Right of First Refusal (except as
collateral for a loan which is secured by the Property, but which is being
retired as of the date hereof).

         The provisions hereof shall bind and inure to the benefit of Assignor
and Assignee, and their respective successors and assigns.

                      [SIGNATURES APPEAR ON FOLLOWING PAGE]





         IN WITNESS WHEREOF, the parties hereto have executed, or caused to be
executed this Assignment as of the date first above written.


ASSIGNOR:

SQUARE 711 DEVELOPER, LLC,
a Delaware limited liability company

By:
    -------------------------------------
    Joseph M. O'Connor
    Executive Manager



ASSIGNEE:

- ------------------------------,
a Delaware limited liability company

By:
       -----------------------------------
Name:
       -----------------------------------
Its:
       -----------------------------------







DISTRICT OF COLUMBIA       )  SS:


         The foregoing Assignment was acknowledged before me on this _____ day
of ___________, 2006, by ______________, as the ________________________ of
_______________________, for the purpose therein contained.


         WITNESS my hand and seal this ________ day of _______________, 2006.



                                  ----------------------------------------
                                  NOTARY PUBLIC



My Commission expires: _______________________











DISTRICT OF COLUMBIA       )  SS:

         The foregoing Assignment was acknowledged before me on this _____ day
of ___________, 2006, by ______________, as the ________________________ of
_______________________, for the purpose therein contained.


         WITNESS my hand and seal this ________ day of _______________, 2006.



                                  ----------------------------------------
                                  NOTARY PUBLIC



My Commission expires: _______________________




                                   EXHIBIT "A"

                                LETTER AGREEMENT
                                ----------------

                                 [SEE ATTACHED]




                                   EXHIBIT "B"

                                  DEED OF GIFT
                                  ------------

                                 [SEE ATTACHED]




                                   EXHIBIT "C"

                      ASSIGNMENT OF LEASE AND OTHER RIGHTS
                      ------------------------------------

                                 [SEE ATTACHED]