The Council may, from time to time, on its own motion or on petition, after at least fifteen (15) days' public notice and hearing as provided by law, amend, supplement or change, modify or repeal the boundaries or regulations herein or subsequently established after submitting same to the Commission for its recommendations and report. The Commission shall have one hundred twenty (120) days after submission to it of any proposed amendment within which to take one (1) of the following actions:

In case the Commission disapproves the change, whether on its own motion or by an action which operates as a disapproval hereunder or in case of a protest against such change duly signed and acknowledged by the owners of thirty percent (30%) or more, either of the area of the land exclusive of streets and places included in such proposed change or within an area determined by lines drawn parallel to and one hundred eighty-five (185) feet distant from the boundaries of the district proposed to be changed, such amendment shall not become effective except by the favorable vote of two-thirds (⅔) of all members of the Council.