The Municipal Council may, from time to time, on its own motion or on petition, amend, supplement, change, modify or repeal, by ordinance, the boundaries of districts or regulations or restrictions herein established. Any proposed amendment shall be first submitted to the Planning and Zoning Commission for its recommendation and report. If the Planning and Zoning Commission makes no report within 45 days, it shall be considered to have made a report approving the proposed amendment.