S.D. Codified Laws § 58-38-11
The contracts by any medical and surgical plan corporation with the subscribers for medical and surgical service shall be entered into only with physicians and surgeons regularly licensed to practice their profession by the State of South Dakota. All contracts issued by such corporation to the subscribers shall constitute direct obligations of the corporation and of the physician or surgeon with whom such corporation has contracted for medical and surgical service and shall provide for medical and surgical service to subscribers by the physician and surgeon chosen by the patient without regard to whether said physician and surgeon has a contract with said corporation, and at the same rate as provided in the contract of the corporation for service by other than contracting physicians and surgeons in case of emergency or expediency.
SDCL 58-38-11