Section 83 - Amendments, alterations and changes in district lines1. The common council may from time to time on its own motion or on petition, after public notice and hearing, which hearing may be held by the council or by a committee of the council or by the planning board, amend the regulations and districts established under any ordinance or local law adopted pursuant to paragraphs twenty-four and twenty-five of section twenty of this chapter. Wherever the owners of fifty per centum or more of the frontage in any district or part thereof shall present a petition duly signed and acknowledged, to the common council, requesting an amendment, supplement, change or repeal of the regulations prescribed for such district or part thereof, it shall be the duty of the council to vote upon said petition within ninety days after the filing of the same by the petitioners with the secretary of the council.2. An amendment shall be effected by a simple majority vote of the council, except that an amendment shall require the approval of at least three-fourths of the members of the council in the event such amendment is the subject of a written protest, presented to the council and signed by:(a) the owners of twenty percent or more of the area of land included in such proposed change; or(b) the owners of twenty percent or more of the area of land immediately adjacent to that land included in such proposed change, extending one hundred feet therefrom; or(c) the owners of twenty percent or more of the area of land directly opposite thereto, extending one hundred feet from the street frontage of such opposite land.