The Board of Trustees of the Village may from time to time on its own motion or on petition, after public notice and hearing, amend, supplement, change, modify or repeal the regulations, restrictions or boundaries herein established. In case, however, of a protest against such change signed by the owners of 20% or more of the area of the land included in such proposed change, or by the owners of 20% or more of the land immediately adjacent extending 100 feet therefrom, or by the owners of 20% or more of the land directly opposite thereto extending 100 feet from the street frontage of such opposite land, such amendment shall not become effective except by the favorable vote of all the members of the Board of Trustees.