<PAGE>   1
                                                                     Exhibit 3.3


                           CERTIFICATE OF AMENDMENT OF
                                  THE BYLAWS OF
                               ARDEN REALTY, INC.


                  The undersigned does hereby certify that:

                  1.       She is the duly elected Secretary of Arden Realty, 
Inc., a Maryland corporation (the "Corporation"); and

                  2. By resolutions duly adopted by written consent of the
Company's Board of Directors dated July 14, 1998, Section 9 and Section 12(c)(3)
of Article II as well as Section 10 of Article III of the Bylaws of the
Corporation's Bylaws were amended as follows:

                                   ARTICLE II

                  Section 9. PROXIES. A stockholder may vote the stock owned of
                  record by him, either in person or by proxy executed in
                  writing by the stockholder or by his duly authorized agent.
                  Such proxy shall be filed with the secretary of the
                  Corporation before or at the time of the meeting. No proxy
                  shall be valid after eleven months from the date of its
                  execution, unless otherwise provided in the proxy.

                  Section 12.  NOMINATIONS AND STOCKHOLDER BUSINESS.

                           (c)      GENERAL.

                                    (3) Notwithstanding the foregoing provisions
                  of this Section 12, a stockholder shall also comply with all
                  applicable requirements of state law and of the Exchange Act
                  and the rules and regulations thereunder with respect to the
                  matters set forth in this Section 12. Nothing in this Section
                  12 shall be deemed to affect any rights of stockholders to
                  request inclusion of proposals in, nor the right of the
                  Corporation to omit a proposal from, the Corporation's proxy
                  statement pursuant to Rule 14a-8 under the Exchange Act.

                                   ARTICLE III

                  Section 10. VACANCIES. If for any reason any or all the
                  directors cease to be directors, such event shall not
                  terminate the Corporation or affect these Bylaws or the powers
                  of the remaining directors hereunder (even if fewer than five
                  directors remain). Any vacancy on the Board of Directors for
                  any cause other than an increase in the number of directors
                  may be filled at any regular meeting or at any special meeting
                  called for that purpose by a 
<PAGE>   2

                  majority vote of the remaining directors, although such
                  majority may be less than a quorum. Any vacancy in the number
                  of directors created by an increase in the number of directors
                  may be filled by a majority vote of the entire Board of
                  Directors. Any individual so elected as director shall serve
                  until the next annual meeting of stockholders and until his
                  successor is elected and qualifies. Any individual elected as
                  a director by stockholders shall serve for the balance of the
                  term to which he is elected and qualifies.

                  IN WITNESS WHEREOF, I have hereunto subscribed my name as of
this 14th day of July, 1998.


                                   By: /s/ DIANA M. LAING 
                                       ------------------
                                   Diana M. Laing, Secretary




                                       2