Any party to a proceeding may be represented by an attorney authorized to practice law in Maryland, or, unless prohibited by law, appear in person or through another legally authorized representative. An attorney shall enter his or her appearance with the Office of Hearings. In an enforcement action initiated by the Department, the signing attorney has entered his appearance. Unless the appearance is subsequently withdrawn in writing, any notice, decision, or other matter required to be sent to a party may be sent to the attorney by first class mail, postage prepaid at the attorney's address, and the presumptions regarding notices to parties will apply. When any party is represented by an attorney, all submissions of evidence, examination and cross-examination of witnesses, and all objections and motions on the parties behalf shall be made solely by that attorney.