EXHIBIT 10.66

                        SIXTH AMENDMENT TO AGREEMENT FOR
                PURCHASE AND SALE AND JOINT ESCROW INSTRUCTIONS
                -----------------------------------------------

          This Sixth Amendment to Agreement of Purchase and Sale and Joint
Escrow Instructions (this "Sixth Amendment") is made as of September 25, 1997 by
and between Kilroy Realty, L.P., a Delaware limited partnership ("Buyer") and
Mission Square Partners, a California general partnership ("Seller") with
respect to the following:

                               R E C I T A L S :
                               - - - - - - - -  

          A.  Seller and Buyer entered into that certain Agreement of Purchase
and Sale and Joint Escrow Instructions providing for the sale of 3750 University
Avenue, Riverside, California as amended by certain amendments to the same
(collectively, the "Agreement");

          B.  Buyer and Seller have discussed reducing the Purchase Price by Six
Hundred Thousand Dollars ($600,000.00), but the parties have not come to a final
agreement regarding the same;

          C.  Buyer and Seller anticipate that additional time will be required
to complete Buyer's review of the Property and to agree upon the terms of the
Purchase Price reduction;

          D.  Seller and Buyer desire to amend the Agreement to provide for such
additional time.

          NOW THEREFORE, in consideration of the mutual covenants and agreements
herein contained and for other good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, Seller and Buyer hereby agree as
follows:

                              A G R E E M E N T :
                              - - - - - - - - -  

          1.  Notwithstanding anything in the Agreement to the contrary, the
Contingency Date, including, but not limited to, for the purpose of Buyer
obtaining the Met Consent, provided for in the Agreement is hereby extended to
October 3, 1997.

          2.  Notwithstanding anything in the Agreement to the contrary, the
Closing Date shall be deemed to be the earlier of (a) October 7, 1997 or (b)
three (3) Business Days after Buyer receives the Met Consent.

          3.  Except as set forth in this Sixth Amendment, the provisions of the
Agreement remain unmodified and in full force and effect.  if any provision of
this Sixth Amendment conflicts with any provision of the Agreement, the
provisions of this Sixth Amendment shall prevail.

          4.  Any capitalized terms which are not defined in this Sixth
Amendment shall have the meaning provided for in the Agreement.

 
          5.  This Sixth Amendment may be signed in counterparts, including
facsimile counterparts, which, when signed by both Buyer and Seller, shall
constitute a binding agreement.

          IN WITNESS WHEREOF, the parties have executed this Sixth Amendment as
of the date first written above.

     "Buyer"                  KILROY REALTY, L.P.,
                              A Delaware limited partnership

                              By: /s/ Tyler Rose
                                 -------------------------------------------
                                 Name: Tyler Rose
                                       -------------------------------------
                                 Title: S.V.P. and Treasurer
                                        ------------------------------------


     "Seller"                 MISSION SQUARE PARTNERS,
                              A California general partnership

                              By: The Betty L. Hutton Title Holding Company,
                                  Inc., (formerly known as The Betty L. Hutton
                                  Company),
                                  its general partner

                                  By:/s/ Thomas C. Parker
                                     ----------------------------------------
                                     Name: Thomas C. Parker
                                           ----------------------------------
                                     Title: C.E.O.
                                            ---------------------------------

                              By: BB&K Mission Square Partners, a California
                                  general partnership,
                                  its general partner

                                  By:/s/ Christopher L. Carpenter
                                     ----------------------------------------
                                     Name: Christopher L. Carpenter
                                           ----------------------------------
                                     Title: General Partner
                                            ---------------------------------

Acknowledgment by Escrow Holder:
- ------------------------------- 

          First American Title Insurance Company hereby acknowledges the terms
of this Sixth Amendment.

Dated:____________, 1997      FIRST AMERICAN TITLE INSURANCE COMPANY

                              By:
                                 --------------------------------------------
                                 Its Authorized Agent

                                      -2-