S.D. Codified Laws § 27A-8-19
The person's next of kin may exercise a substituted informed consent in accordance with the requirements in § 27A-8-15 for the sole purpose of admission to an inpatient psychiatric facility or the center. Upon the exercise of such a substituted informed consent, the facility director or center administrator may admit the person as a voluntary patient for a period not to exceed fourteen days if the criteria in subdivisions 27A-8-1(1) to (3), inclusive, and (5), are met. During the fourteen-day admission period, the consenting next of kin may file a petition in circuit court for an order authorizing the appointment of the petitioner as guardian of the person for continuing the admission. If a petition is timely filed, admission of a nonobjecting person may continue until the court hearing. If a petition is not filed, the person shall be discharged upon the expiration of the fourteen-day admission period.
SDCL 27A-8-19