10 U.S.C. § 655: Designation of persons having interest in status of a missing member

(a) The Secretary concerned shall, upon the enlistment or appointment of a person in the armed forces, require that the person specify in writing the person or persons, if any, other than that person’s primary next of kin or immediate family, to whom information on the whereabouts and status of the member shall be provided if such whereabouts and status are investigated under chapter 76 of this title. The Secretary shall periodically, and whenever the member is deployed as part of a contingency operation or in other circumstances specified by the Secretary, require that such designation be reconfirmed, or modified, by the member. (b) The Secretary concerned shall, upon the request of a member, permit the member to revise the person or persons specified by the member under subsection (a) at any time. Any such revision shall be in writing.