Written notice of a hearing shall be sent by the Board to all interested parties at least 30 days before the hearing. The notice shall state the: Date, time, and place of the hearing; Issues or charges involved in the proceeding, provided, however, that if by reason of the nature of the proceeding, the issues cannot be fully stated in advance of the hearing, or if subsequent amendment of the issues is necessary, they shall be fully stated as soon as practicable. Services upon a party shall be by delivery of the charging document and copy of the complaint to the party in person. Instead of personal service, the Board may serve the charging document and a copy of the complaint by registered or certified mail, restricted delivery, return receipt requested.