A. No existing structure devoted to a use not permitted by this Part 1 in the district in which it is located shall be enlarged, extended, constructed, reconstructed, moved or structurally altered except in changing the use of the structure to a use permitted in the district in which it is located;
B. Any nonconforming use may be extended throughout any parts of a building which were manifestly arranged or designed for such use at the time of adoption or amendment of this Part 1, but no such use shall be extended to occupy any land outside such building;
C. If no structural alterations are made, any nonconforming use of a structure, or structure and premises, may as a special exception be changed to another nonconforming use, provided that the Zoning Hearing Board, either by general rule or by making findings in the specific case, shall find that the proposed use is equally appropriate or more appropriate to the district than the existing nonconforming use. In permitting such change, the Zoning Hearing Board may require appropriate conditions and safeguards in accord with the provisions of this Part 1;
D. Any structure, or structure and land in combination, in or on which a nonconforming use is superseded by a permitted use, shall thereafter conform to the regulations for the district, and the nonconforming use may not thereafter be resumed;
E. When a nonconforming use of a structure, or structure and premises in combination, is discontinued or abandoned for six consecutive months or for 18 months during any three-year period (except when government action impedes access to the premises), the structure, or structure and premises in combination, shall not thereafter be used except in conformity with the regulations of the district in which it is located;
F. Where nonconforming use status applies to a structure and premises in combination, removal or destruction of the structure shall eliminate the nonconforming status of the land. "Destruction" for the purpose of this subsection is defined as damage to an extent of more than 50% of the replacement cost at time of destruction.