Any sign which was lawful prior to the adoption, revision or amendment of this § 23-12, but which fails to conform to the requirements of these regulations, shall be deemed a nonconforming sign.

Any nonconforming sign may be continued on the lot or structure on which it is located, so long as the nonconforming sign is not enlarged, extended, reconstructed or structurally altered; provided, however, that a nonconforming sign may be structurally altered to correct an unsafe condition. A nonconforming sign may be restored or repaired in the event of partial destruction thereof if such destruction does not exceed 65% of the value of the sign immediately prior to such partial destruction.

Upon a change of use or occupant, the message of a nonconforming sign may be altered to reflect the change; provided, however, that any such change shall not enlarge, extend, reconstruct or structurally alter the nonconforming sign or change its method of illumination unless the enlargement, extension, reconstruction or alteration shall bring the sign into conformity with this section.