S.D. Codified Laws § 29A-5-416

If there is more than one guardian or conservator, a majority must concur to exercise a power unless a guardian or conservator has delegated powers to another guardian or conservator or the court has authorized the exercise of powers by less than a majority. However, a delegation, whether by court authorization or otherwise, does not immunize a guardian or conservator from liability for a breach of fiduciary duty committed by another guardian or conservator if the guardian or conservator participated in the breach, approved of, acquiesced in, or concealed the breach, negligently permitted the breach to occur, or had actual knowledge of the breach and failed to take reasonable corrective action.