S.D. Codified Laws § 58-33-83
If any life insurance policy or health insurance policy is canceled before its renewal date or expiration date, other than by the death of the insured, and the insured has paid premiums in advance on the policy, the insurer shall refund to the owner of the policy the unearned portion of the premiums paid beyond the end of the month in which the cancellation occurred.
A cancellation of an automatic bank draft authorization does not constitute a request for cancellation of the policy. In the event of a cancellation of an automatic bank draft authorization without a request for cancellation of the policy, all applicable grace periods shall be provided.
This section applies to all life insurance policies, except group life insurance policies, and to all health insurance policies, except medicare supplement policies as defined in § 58-17A-1 and long term care policies as defined in § 58-17B-2.
SDCL 58-33-83