EXHIBIT 10.63 THIRD AMENDMENT TO AGREEMENT FOR PURCHASE AND SALE AND JOINT ESCROW INSTRUCTIONS ----------------------------------------------- This Third Amendment to Agreement of Purchase and Sale and Joint Escrow Instructions (this "Third Amendment") is made as of September 19, 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 that certain First Amendment and that certain Second Amendment to the same (collectively, the "Agreement"); B. Buyer and Seller anticipate that additional time will be required to complete Buyer's review of the Property; C. 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 provided for in the Agreement is hereby extended to September 22, 1997. 2. Seller acknowledges that, as provided for in the First Amendment to the Agreement, Buyer shall have until September 25, 1997 to terminate the Agreement if it has not obtained the Met Consent on or before such date. 3. Except as set forth in this Third Amendment, the provisions of the Agreement remain unmodified and in full force and effect. If any provision of this Third Amendment conflicts with any provision of the Agreement, the provisions of this Third Amendment shall prevail. 4. Any capitalized terms which are not defined in this Third Amendment shall have the meaning provided for in the Agreement. 5. This Third 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 Third Amendment as of the date first written above. "Buyer" KILROY REALTY, L.P., a Delaware limited partnership By: /s/ Nadine K. Kirk ---------------------------------------------- Name: Nadine K. Kirk ----------------------------------------- Title: V.P. - Legal ---------------------------------------- "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: Partner ------------------------------------ Acknowledgment by Escrow Holder: - ------------------------------- First American Title Insurance Company hereby acknowledges the terms of this Third Amendment. Dated:__________________, 1997 FIRST AMERICAN TITLE INSURANCE COMPANY By:_________________________________________ Its Authorized Agent -2-