S.D. Codified Laws § 12-18-6.3
The person making an application for ballots shall announce his or her name and present his or her personal identification. A member of the precinct election board shall then verify that the picture on the personal identification presented under § 12-18-6.1 matches such person and that the name on the personal identification appears on the voter registration list pursuant to § 12-18-7.1. If the member cannot determine from the personal identification presented that the person making an application for ballots is the person listed on the voter registration list, the member may consider other forms of identification, personal knowledge and an explanation from the person making an application for ballots to match that person's name to a name on the registration list. If identity cannot be proven to the satisfaction of the member of the precinct election board or if the person making an application for ballots is challenged on the basis of identity by a member or a poll watcher, the person may vote a provisional ballot.
SDCL 12-18-6.3