FIRST AMENDMENT TO AGREEMENT OF SALE

     THIS FIRST AMENDMENT TO AGREEMENT OF SALE (this "Amendment"), is entered
into as of the 8th day of November, 1996, by and between Transwestern
Investment Company, L.L.C., ("Purchaser"), and Union Tower Limited Partnership,
an Illinois Limited Partnership ("Seller").

                             W I T N E S S E T H:

     A.   Purchaser and Seller have heretofore entered into a certain Agreement
of Sale dated October 10, 1996 ("Agreement") for the purchase and sale of the
property commonly known as Union Tower, located in Lakewood, Colorado.

     B.   Purchaser and Seller now desire to amend the Agreement to change the
Closing Date and extend the Inspection Period (as those terms are defined in
the Agreement).

     NOW, THEREFORE, for good and valuable consideration, the receipt and
sufficiency of which are hereby acknowledged, the parties hereto hereby agree
as follows:

     1.   The Closing Date, as defined in Paragraph 8 of the Agreement, is
hereby changed to December 16, 1996.

     2.   The expiration of the Insepction Period (as defined in Paragraph 7.1
of the Agreement) is hereby extended to 2:00 p.m. Chicago time on November 15,
1996.

     3.   Except as specifically modified herein, the terms and conditions of
the Agreement shall remain unchanged and in full force and effect.

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

                              PURCHASER:

                              TRANSWESTERN INVESTMENT COMPANY, L.L.C.


                              By:   /s/ Stephen R. Quazzo
                                   ---------------------------------
                              Name:     Stephen R. Quazzo
                                   ---------------------------------
                              Its:      Managing Director
                                   ---------------------------------


                              SELLER:

                              UNION TOWER LIMITED PARTNERSHIP,
                              an Illinois limited partnership


                              By:  Union Tower Partners, Inc.,
                                   its general partner


                                   By:   /s/ James E. Mendelson
                                        ----------------------------------
                                   Name:     
                                        ----------------------------------
                                   Its:
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