S.D. Codified Laws § 21-10-14

If the complaint in an action pursuant to § 21-10-11 is filed by a citizen, it shall not be dismissed except upon a sworn statement made by the plaintiff and his attorney setting forth the reasons why the action should be dismissed, and the dismissal approved by the state's attorney, in writing, or in open court. If the court is of the opinion that the action ought not to be dismissed, he may direct the state's attorney to prosecute said action to judgment, and if the action is continued more than one term of court, any citizen of the county or the state's attorney may be substituted for the party plaintiff and prosecute said action to judgment.