At any time after the filing of a map of the kind described in section 40-48-28 for record with the recorder and during the period specified for the reservation, the planning commission and the owner of any land containing a reserved street location may agree upon a modification of the location of the lines of the proposed street. Such agreement shall include a release by the owner of any claim for compensation or damages by reason of such modification. Thereupon, the commission may make a map corresponding to the modification and transmit the map to the governing body. If the modified map is approved by the governing body, the city auditor shall file for record an attested copy thereof with the recorder, and the modified map shall take the place     of the original map. The governing body, by resolution, may abandon any reservation at any time. Any such abandonment shall be filed for record with the recorder.