S.D. Codified Laws § 29A-1-108

For the purpose of granting consent or approval with regard to the acts or accounts of a personal representative or trustee, and for purposes of consenting to modification or termination of a trust or to deviation from its terms, the sole holder or all co-holders of a presently exercisable general power of appointment are deemed to act for beneficiaries to the extent their interests (as objects, takers in default, or otherwise) are subject to the power.