(a) Council may, on its own motion or on petition, after public notice, filing of documents, and hearing required by law, amend this Zoning Ordinance in any respect. No amendment shall be passed unless it shall have first been submitted to the Planning and Zoning Commission for its consideration, and the Commission has been allowed a reasonable time, not less than thirty days, for report. However, any amending ordinance submitted to Council by the Commission may be passed without further references to the Commission.
(b) Whenever the owners of more than fifty percent (50%) of the land in any area present to Council a petition, duly signed and acknowledged, requesting any amendment, supplement or change in the regulations or zoning prescribed for the area, it shall be the duty of the Council to vote upon the petition within ninety days of its presentation.
(c) The changes of the zoning or districting of any area by any amendment hereafter passed shall not change the regulations of this Zoning Ordinance with respect to buildings, structures, or the use of premises existing at the time of the passage of such amendment.
(1973 Code Section 151.24.)