If a protest against an amendment, change or repeal of this title or any part thereof be presented, duly signed and acknowledged by the owners of twenty percent (20%) or more of the area of the lots immediately abutting either side of the territory included in such proposed change, or separated therefrom only by an alley or street, such amendment shall not be passed, except by the favorable vote of the city council. (1990 Code § 12-395)