Nothing herein contained shall require any change in the principal construction or designated use of a building for which a permit has been heretofore issued, and the construction of which such building shall have been actually begun at the time of the passage of this act. If any area in any particular zone is hereafter transferred to another zone by change in zone boundaries, the provisions of this section with regard to buildings or premises then existing, or building permits then issued at the time of the adoption of this act shall apply to buildings or premises existing or building permits issued in such transferred area at the time of such transfer. (Ord. 504, 1-8-2008)