Mo. Rev. Stat. § 472.445
Unless otherwise ordered by the court, directed by the principal, or provided by a power of attorney, a custodian shall disclose to an agent with specific authority over digital assets or general authority to act on behalf of a principal a catalogue of electronic communications sent or received by the principal and digital assets, other than the content of electronic communications, of the principal if the agent gives the custodian:
(4) If requested by the custodian for the purpose of identifying the correct account of the correct user:
(L. 2018 H.B. 1250)