A party who has signed a written contract may be compelled specifically to perform it, though the other party has not signed it, if the latter has performed, or offers to perform it on his part, and the case is otherwise proper for enforcing specific performance.
S.D. Codified Laws § 21-9-8
Performance or offer to perform in lieu of signature of written contract
Source: CivC 1877, § 1997; CL 1887, § 4630; RCivC 1903, § 2342; RC 1919, § 2013; SDC 1939 & Supp 1960, § 37.4606.
Official source: South Dakota Legislature. Reproduced from public-domain South Dakota statutes; confirm against the official source for the current text. Not legal advice.