The Board of Mayor and Selectmen may, from time to time, on its own motion or on petition, after public notice and hearing, amend the districts and the regulations established therefor in accordance with the provisions of section 3594, Mississippi Code (MCA 1972, § 17-1-17). In case a protest against such change is signed by the owners of twenty (20) percent of either the area of the lots included in such proposed change or of those immediately adjacent to the rear thereof, extending one hundred sixty (160) feet from the street frontage of such opposite lots, such amendment shall not become effective except by the favorable vote of two-thirds (2/3) of all of the members of the legislative body of this [city].

Every proposed amendment shall be first referred to the Planning Commission for report, and any amendment that has failed to receive the approval of the Planning Commission shall not be passed by the governing body except by the affirmative vote of two-thirds (2/3) of the legislative body of the [city].