S.D. Codified Laws § 32-5-171
If the ownership of a motor vehicle with an emblem specialty plate is transferred or assigned, the transferor shall remove the emblem specialty plates from the vehicle and shall receive a credit for the unexpired time on the registration if the plates are attached to another vehicle. The county treasurer shall process a new registration indicating the motor vehicle to which the emblem specialty plates are to be transferred and send it to the department. The secretary shall make the necessary changes in the registration system and the credit shall be applied. The department shall notify the transferor of any corrections which need to be made.
No credit may be issued if the emblem specialty plate is detached and not reattached to another motor vehicle. If the transferor fails to remove the emblem specialty plates pursuant to this section, the transferor loses any credit and the plates are no longer valid. A violation of this section is a Class 2 misdemeanor.
SDCL 32-5-171