Each such group health insurance policy shall contain in substance a provision that, in the absence of fraud, all statements made by applicants or the policyholder or by an insured person shall be deemed representations and not warranties, and that no statement made for the purpose of effecting insurance shall avoid such insurance or reduce benefits unless contained in a written instrument signed by the policyholder or the insured person, a copy of which has been furnished to such policyholder or to such person or his beneficiary.
SDCL 58-18-8