Mo. Rev. Stat. § 376.699
If any individual insured under a group life insurance policy hereafter delivered in this state becomes entitled under the terms of such policy to have an individual policy of life insurance issued without evidence of insurability, subject to the making of an application and paying the first premium within the period specified in such policy, and if such individual is not given notice of the existence of such right at least fifteen days prior to the expiration date of such period, then, in such event, the individual shall have an additional period within which to exercise such right. Nothing contained herein shall be construed to continue any insurance beyond the period provided in such policy. The additional period provided in this section shall expire fifteen days after the individual is given the notice of his rights regarding an individual policy, but in no event shall such additional period extend beyond sixty days after the expiration date of the period provided in such policy. Written notice presented to the individual or mailed by the policyholder to the last known address of the individual, or mailed by the insurer to the last known address of the individual as furnished by the policyholder, shall constitute notice for the purpose of this section.
§ 376.699, RSMo