Change of use. Any nonconforming use may be changed to any conforming use or, on application to and with the approval of the Board of Appeals, to any use which the Board of Appeals deems to be more similar in character with the uses permitted in the district in which said change of use is proposed. Any nonconforming use may be changed to a conforming use, even if the building or structure occupied by said use is noncomplying as to bulk; provided, however, that said change must be approved by the Zoning Board of Appeals and is subject to all other applicable requirements including site plan approval. No nonconforming uses, buildings or other structures, if once changed to conform with this chapter, shall thereafter be changed so as to be made nonconforming.