Mo. Rev. Stat. § 42.035
Notwithstanding any other provision of law a veteran who is homeless may use the post office box or voice mail address of any charitable organization or religious organization as those terms are defined in section 407.453, or fraternal or veterans' organization, provided that the legitimate purpose of such organization is to provide charitable, religious, fraternal, veterans services and provided that such organization has been providing such legitimate services for a period of at least ten years, as a substitute address on any applications or forms which are necessary to receive any type of assistance from the state or federal government and which require an address or voice mail address, so long as the charitable or religious organization is willing to provide such post office box or voice mail address to the homeless veteran for his or her use.
§ 42.035, RSMo