Once a nonconforming use or structure has been changed or altered so as to comply with the pertinent district provisions of this Chapter, it shall not revert back to a nonconforming use or structure. Once the Zoning Board of Appeals has permitted the substitution of a more or equally restrictive nonconforming use for an existing nonconforming use pursuant to the provisions of Article N, the existing use shall lose its status as a legal nonconforming use and become subject to all the conditions required by the Zoning Board of Appeals and pertinent zoning district. Substitution of new equipment may be permitted by the Zoning Board of Appeals if such equipment will reduce the incompatibility of the nonconforming use with the neighboring uses.