Mo. Rev. Stat. § 454.1611: Employer's receipt of income withholding order of another state.

An income withholding order issued in another state may be sent by or on behalf of the obligee, or by the support enforcement agency, to the person defined as the obligor's employer under section 452.350 or 454.505 without first filing a petition or comparable pleading or registering the order with a tribunal of this state.