1.   The Council may on its own motion or on petition after public notice and hearing as provided by law, and after report by the Planning and Zoning Commission, amend, supplement or change the boundaries or regulations herein or subsequently established. Any owner or owners of property may present a petition duly signed and verified, requesting an amendment, supplement or change in the regulations prescribed for a district or part thereof. Such petition shall be signed by the owners of at least 50 percent of the property within 300 feet therefrom, and said petition shall be filed with the Planning and Zoning Commission.

   2.   The Commission shall make a report to the Council within 60 days from the date of receipt of such petition. In case the proposed amendment, supplement or change is disapproved by the Commission, or in case of a protest against any proposed amendment or change signed by the owners of 20 percent or more of the area of the lots included in the proposed amendment or change, or by the owners of 20 percent or more of the property which is located within 200 feet of the exterior boundaries of the property for which the amendment or change is proposed, such amendment shall not become effective except by the favorable vote of at least three-fourths of all members of the Council.