S.D. Codified Laws § 58-17-109
Any disability income insurance policy may include provisions that exclude or reduce benefits if the insured is collecting other benefits under a government program or is eligible to receive benefits under other insurance coverage. If the insured subsequently receives other benefits for a period for which the insurer paid benefits, the insurer may require reimbursement from the insured for any benefits already paid that otherwise would not have been paid. If the insured fails to make timely application for any other insurance coverage or governmental program for which that insured may be eligible, fails to actively and in good faith pursue all appeals procedures if benefits under other insurance or governmental program have been denied, or fails to produce satisfactory evidence that the applications have been made and the appeals pursued, benefits may be reduced or withheld.
SDCL 58-17-109