SDCL § 3-12C-1210: Irrevocable benefit election by generational members.

If more than one monthly retirement benefit payment has been made to the generational member, the benefit election made by a member is irrevocable and surviving spouse benefits, if elected, may only be paid to the person who is the spouse both at the time of the election and at the time of the member's death and only if the spouse survives the member. The benefit election may not be rescinded in the event of a subsequent divorce or the subsequent death of the spouse.