Mo. Rev. Stat. § 115.569: Depositions, when taken — civil discovery rules to apply.

Immediately upon the filing of a petition and answer, the taking of depositions may commence at the option of the contestant, and the persons selected by the contestant and contestee to take depositions shall immediately issue subpoenas to the witnesses, commanding them to appear and give testimony at the time and place specified. The taking of depositions and all related matters shall be subject to the rules of discovery in civil cases. Either the contestant or the contestee may, without notice, take rebutting testimony at the time and place specified for the taking of depositions.