(a) Who may request a hearing. You may request a hearing if a hearing is available under § 404.930. In addition, a person who shows in writing that his or her rights may be adversely affected by the decision may request a hearing.

(b) Who are parties to a hearing. After a request for a hearing is made, you, the other parties to the initial, reconsidered, or revised determination, and any other person who shows in writing that his or her rights may be adversely affected by the hearing, are parties to the hearing. In addition, any other person may be made a party to the hearing if his or her rights may be adversely affected by the decision, and we notify the person to appear at the hearing or to present evidence supporting his or her interest.