The director shall revoke the authority of a domestic mutual insurer to issue policies without contingent liability if at any time the insurer's assets are less than the sum of its liabilities and the surplus required for the authority, or if the insurer, by resolution of its board of directors approved by a majority of its members, requests that the authority be revoked. During the absence of the authority the insurer may not issue a policy without including a provision for the contingent liability of the policyholder or renew a policy that is renewable at the option of the insurer without an endorsement providing for the contingent liability.