S.D. Codified Laws § 27A-10-19
If any person presents to a facility licensed by the state as a hospital or designated as an appropriate regional facility, other than the Human Services Center, and after an examination by a qualified mental health professional it is determined that the person is severely mentally ill and in such condition that immediate intervention is necessary to protect the person from physical harm to self or others, the qualified mental health professional may initiate a twenty-four-hour hold on the person and retain the person at the hospital or appropriate regional facility for purposes of observation and emergency treatment. The hospital, the appropriate regional facility, or the qualified mental health professional shall notify the chair of the county board of mental illness of the twenty-four-hour hold. The qualified mental health professional shall petition for commitment of the person according to §§ 27A-10-1 and 27A-10-4. The person shall be afforded rights according to § 27A-10-5. If a petition for emergency commitment pursuant to § 27A-10-1 is not filed within twenty-four hours, the person must be released.
SDCL 27A-10-19