If lawful use involving individual structures with an assessed value in an amount as set by the City Council, and amended by resolution from time to time, or of structure and premises in combination, exists at the effective date of adoption of this ordinance that would not be allowed in the district under the terms of this ordinance, the lawful use may be continued so long as it remains otherwise lawful, subject to the following provisions:
(A) No existing structure devoted to a use not permitted by this ordinance 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 that use at the time of adoption or amendment of this ordinance, but no such use shall be extended to occupy any land outside that building;
(C) If no structural alterations are made, any nonconforming use of a structure, or structure and premises, may be changed to another nonconforming use provided that the proposed use is equally appropriate or more appropriate to the district than the existing nonconforming use. Whenever a nonconforming use has been changed to a conforming use, or to a use permitted in a district of greater restrictions, it shall not thereafter be changed to a nonconforming use; and
(D) Where nonconforming use status applies to a structure and premises in combination, removal or destruction of the entire structure shall eliminate the nonconforming status of land.