Whenever the owners of 50% or more of the road frontage in any district or any specific part thereof shall present to the Town Board a petition, duly signed and acknowledged, requesting an amendment, supplement, change, modification or repeal of the regulations prescribed or of the Official Zoning Map including said district or specified part thereof, it shall be the duty of the Town Board to hold a public hearing thereon and cause notice thereof to be given in the manner prescribed below.