EXHIBIT 10.18

                               AMENDMENT NO. 1 TO
               THE AMENDED AND RESTATED PRENTISS PROPERTIES TRUST
                         TRUSTEES' SHARE INCENTIVE PLAN

                             AS OF OCTOBER 23, 2002


         This Amendment by Prentiss Properties Trust to the Amended and Restated
Prentiss Properties Trust Trustees' Share Incentive Plan (the "Plan"), made
pursuant to the right to amend reserved in Article X of the Plan, amends and
modifies the Plan as follows:

         1. The following shall be added to the end of Article X:

            "Notwithstanding the above or anything in this Plan to the
            contrary, except as provided in Section 2.02, the
            Administrator shall not have the power to adjust the price per
            Share of Shares purchased on the exercise of an Option without
            the consent of the Company's shareholders."

         2. In all other respects, the Plan shall remain unchanged and in full
force and effect.

         IN WITNESS WHEREOF, the foregoing Amendment is hereby duly executed by
the corporate officer signing below on October 23, 2002.

                                       PRENTISS PROPERTIES TRUST



                                       By: /s/ Thomas F. August
                                           -------------------------------------
                                           Thomas F. August
                                           President and Chief Executive Officer