Mo. Rev. Stat. § 492.020: Oaths required to be taken before particular officer may be taken before others, when.

Whenever any oath or affirmation is required by law to be taken before a particular court or officer, the same may be done before any other court or officer empowered to administer oaths, unless it is expressly prohibited; and when no court or officer is named by whom an oath may be administered or affidavit taken, the same may be done by any court or officer authorized to administer oaths.