S.C. Code Ann. § 56-3-2830

A license plate issued pursuant to this article may be transferred to another vehicle of the same weight class owned by the same person upon application being made therefor, in a manner and upon forms which must be prescribed by the Department of Motor Vehicles, and upon approval of the application by the Department. It is unlawful for any person to whom a plate has been issued pursuant to this article knowingly to permit it to be displayed on any vehicle except that one authorized by the Department. If a holder of the plate ceases to be a volunteer fireman he must immediately return the plate to the Department.