Mo. Rev. Stat. § 454.1548: Proceedings under act.

(a) Except as otherwise provided in sections 454.1500 to 454.1728, this article, sections 454.1548 to 454.1602, applies to all proceedings under sections 454.1500 to 454.1728.

(b) An individual petitioner or a support enforcement agency may initiate a proceeding authorized under sections 454.1500 to 454.1728 by filing a petition in an initiating tribunal for forwarding to a responding tribunal or by filing a petition or a comparable pleading directly in a tribunal of another state or foreign country which has or can obtain personal jurisdiction over the respondent.