(a) If during a conference hearing the presiding officer has reason to believe that material facts are in dispute, the presiding officer may require any party to state the identity of the witnesses or other sources through whom the party would propose to present proof if the proceeding were converted to a formal hearing, but if disclosure of any fact, allegation or source is privileged or expressly prohibited by any provision of law, the presiding officer may require the party to indicate that confidential facts, allegations or sources are involved, but not to disclose the confidential facts, allegations or sources.

(b) If during a conference hearing a party has reason to believe that essential facts must be obtained in order to permit an adequate presentation of the case, the party may inform the presiding officer regarding the general nature of the facts and the sources from whom the party would propose to obtain those facts if the proceeding were converted to a formal hearing.