Unless such proposed amendment, supplement or change has been approved by the city planning commission or if a protest against such amendment, supplement or change has been filed with the building inspector, duly signed and acknowledged by the owners of twenty (20) percent or more, either of the area of the lots included in such proposed change, or those immediately adjacent in the rear thereof extending two hundred (200) feet therefrom, or of those directly opposite thereto extending two hundred (200) feet from the street frontage of such opposite lots, such amendment, supplement or change shall not become effective except by a three-fourths (3/4) vote of the city council. Provided, however, should any such proposed amendment, supplement or change be not approved by the city council, then the same amendment, supplement, or change shall not be proposed at any time prior to the expiration of six (6) months from the date of the action of the city council in disapproving such proposed amendment, supplement or change.