S.D. Codified Laws § 34A-6-1.15

The procedure to amend a permit may be initiated by an application filed by the owner of the facility or by a petition filed by the department or a member of the board specifying the requested modification and the reasons for it. A request for amendment shall be granted if it is demonstrated that the change is necessary to meet the requirements established by §§ 34A-6-1.1 to 34A-6-1.38, inclusive, and is in the public interest or, in the case of a request by the permit holder, that the change will meet the requirements of §§ 34A-6-1.1 to 34A-6-1.38, inclusive, and is in the public interest.