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                                                                   EXHIBIT 10.27

                          Mack-Cali Texas Property L.P.
                                11 Commerce Drive
                           Cranford, New Jersey 07016

                                January 25, 2002

Centennial Acquisition Company
5001 LBJ Freeway, Suite 900
Dallas, Texas 75244
Attention: Mr. Steven H. Levin

Ashwood American Properties, Inc.
2001 Ross Avenue, Suite 3160
Dallas, Texas 75201
Attention: Mr. David S. Gruber

               Re:  Agreement of Sale and Purchase Between Mack-Cali Texas
                    Property L.P. ("Seller") and Centennial Acquisition Company
                    and Ashwood American Properties, Inc. (collectively,
                    "Purchaser") DATED AS OF DECEMBER 14, 2001 (THE "PURCHASE
                    AGREEMENT")

Gentlemen:

     This letter will clarify certain matters relating to the Mezzanine Loan,
the MBRK Lease, the expiration of the Evaluation Period and due diligence
communications. All capitalized terms used but not defined herein shall have the
meanings assigned to them in the Purchase Agreement.

     1.   MEZZANINE LOAN. Under Section 5.1(b)(y) of the Purchase Agreement,
Purchaser agreed to pay all reasonable costs incurred by Seller and Mezzanine
Lender in connection with the closing of the Mezzanine Loan from Mezzanine
Lender to Purchaser, including but not limited to attorneys' fees, up to
Twenty Thousand Dollars ($20,000). Said Section 5.1(b) further provides that
Seller and Purchaser shall agree on forms of the Mezzanine Loan Documents
during the Evaluation Period. Purchaser hereby confirms and acknowledges that
nothwithstanding said provision, Purchaser has requested that Seller not
commence preparation of the Mezzanine Loan Documents until authorized to do
so by Purchaser, and, as of the date hereof, Purchaser has not yet authorized
Seller to commence preparation of the Mezzanine Loan Documents. Purchaser
hereby acknowledges and confirms that, whether or not the Closing occurs,
except in the event the Closing does not occur by reason of a default under
the Purchase Agreement by Seller, Purchaser shall pay all reasonable costs of
counsel incurred by Seller and Mezzanine Lender in connection with the
preparation of the Mezzanine Loan Documents, up to $20,000.

     2.   MBRK LEASE. MBRK has vacated its leased premises and, under
Section 7.1(a) of the Purchase Agreement, Seller may, prior to Closing, bring
suit against, settle disputes with, and negotiate the surrender of the Lease of
MBRK with the prior written consent of Purchaser, which consent may be withheld
in Purchaser's sole and absolute discretion, provided that Purchaser's consent
shall not be required for a settlement with MBRK if (i) Purchaser receives the
MBRK Credit at Closing in accordance with Section 10.4(b) of the Purchase
Agreement and,

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(ii) as a result of such settlement, there is no decrease in the Rental payable
by MBRK under the MBRK Lease after the Closing Date. Seller and Purchaser hereby
further agree that Seller may, until the Closing, pursue collection of
Delinquent Rental owed by MBRK under the MBRK Lease through the Closing,
including without limitation amounts owed pursuant to the Summary Judgment, and
commencement and pursuit of litigation against MBRK to collect additional
Delinquent Rental through the Closing, and may enter into a settlement agreement
with MBRK with respect to such Delinquent Rental and Summary Judgment, without
first obtaining Purchaser's consent, provided that (1) the res judicata benefit,
if any, of the Summary Judgment is not adversely affected thereby, and (2)
neither the rights of Purchaser nor the obligations of MBRK under the MBRK Lease
after Closing (including, without limitation, the amount of Rental MBRK is
obligated to pay under the MBRK Lease after the Closing) are adversely affected
by such collection or settlement. The right of Seller to pursue the collection
of Delinquent Rental payable by MBRK for the period after December 31, 2001 is
subject to the caveat that, if Closing shall occur, any such Delinquent Rental
collected by Seller shall be subject to the priority of payment set forth in the
penultimate sentence of Section 10.4(b) of the Purchase Agreement.

     3.   EVALUATION PERIOD. Notwithstanding anything to the contrary contained
in the Purchase Agreement, the Evaluation Period will expire at 5.00 p.m.
Eastern Time on February 12, 2002.

     4.   DUE DILIGENCE COMMUNICATIONS. Purchaser and Seller hereby agree that,
notwithstanding the provisions of Section 14.1 of the Purchaser Agreement, with
respect to due diligence matters only, communications to Purchaser shall be
to the following:

                       Ashwood Companies, Inc.
                       8625 King George Drive, Suite 225
                       Dallas, Texas 75235
                       Attention: Mr. Gary Horn
                       Phone: (214) 215-2497
                       Fax:(214) 638-7230

     5.   MISCELLANEOUS. This letter agreement may be executed in any number of
counterparts, all of which taken together will constitute one and the same
instrument, and the signature page of any counterpart may be removed therefrom
and attached to any other counterpart. This letter agreement shall be legally
binding upon receipt by each party of the facsimile or the original signature of
Seller and of Purchaser.

     Please evidence your agreement to the terms of this letter by executing
this letter in the space provided below.

                               MACK-CALI TEXAS PROPERTY L.P.

                               By: Mack-Cali Sub XVII, Inc., its general partner

                               By: /s/ Roger W. Thomas
                                  ----------------------------------------------
                               Name:   Roger W. Thomas
                                    --------------------------------------------
                               Title:  Executive Vice President &
                                       General Counsel
                                     -------------------------------------------

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ACCEPTED AND AGREED TO AS OF THE DATES SET FORTH BELOW:

CENTENNIAL ACQUISITION COMPANY             January 24, 2002

By:    /s/ Steven H. Levin
      --------------------------------
Name:      Steven H. Levin
Title:     President


ASHWOOD AMERICAN PROPERTIES, INC.,         January 25, 2002

By:    /s/ David S. Gruber
      --------------------------------
Name:      David S. Gruber
Title:     Chairman/CEO


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