(a) The parties to a hearing, their attorneys or representatives, their witnesses and any witness called by the hearing officer may be present at the hearing. Other persons may be admitted upon the hearing officer's discretion. Upon the hearing officer's motion, or upon the motion of either party, potential witnesses may be excluded from the hearing during the testimony of other witnesses.

(b) An individual representing the appellant must have a written authorization signed by the appellant if the appellant is not present.