S.D. Codified Laws § 2-15-15
If at or about the time of submitting any such amendment, Congress shall either in a resolution submitting the same or by statute, prescribe the manner in which the conventions shall be constituted, and shall not except from the provisions of such statute or resolution such states as may theretofore have provided for constituting such conventions, the preceding provisions of this chapter shall be inoperative, the convention shall be constituted and shall operate as the said resolution or act of Congress shall direct, and all officers of the state who may by the said resolution or statute be authorized or directed to take any action to constitute such a convention for this state are authorized and directed to act thereunder and in obedience thereto with the same force and effect as if acting under a statute of this state.
SDCL 2-15-15