021-3 Wyo. Code R. § 3-8
(a) Upon written motion, a person may be added as a party to the hearing, provided that the movant claims a substantial interest relating to the application and claims that the disposition of the application may adversely affect his ability to protect that interest. The motion shall state in detail why the person seeks to become a party to the hearing and shall be filed with the Commissioner at least fourteen (14) days before the hearing date. The Commissioner shall promptly deliver a copy of the motion to the Chairman and to the presiding officer. The movant shall serve a copy of the motion on all other parties contemporaneously with the filing of the motion.
(b) Each party may file a written response to the motion with the Commissioner within two (2) days after the date on which the motion was served on such responding party. The Commissioner shall promptly deliver a copy of the response to the Chairman and to the presiding officer. Each responding party shall serve a copy of the response on all other parties.
(c) As soon as reasonably practicable, but at least twenty-four (24) hours before the prehearing conference, the presiding officer shall notify the parties in writing of his decision. No oral argument is permitted.
(d) If the presiding officer grants the motion, the movant becomes a party to the hearing with the right, to the same extent as the applicant and fully subject to these Regulations, to participate in the prehearing conference, to receive formal notices, to appear, argue and be heard at the hearing, to submit documentary and other evidence, to produce and cross-examine witnesses at the hearing and to file a brief on relevant issues.
(e) This Section does not limit a persons right to attend and participate in a hearing as a member of the public.
021-3 Wyo. Code R. § 3-8