(a) Postponements of hearings will not be allowed upon the request of any party or the Bureau except upon a showing of good cause and proper diligence. A request for a postponement must be served upon all parties to the proceeding and filed in the office of the administrative law judge at least 10 days prior to the date of the hearing. In no case will a request for postponement served or filed less than 10 days in advance of the hearing or made at the hearing be granted unless the party requesting it demonstrates that an extreme emergency occurred which could not have been anticipated and which justifies beyond question the granting of a postponement. In any such emergency, if time does not permit the filing of such request prior to the hearing, it may be made orally at the hearing.
(b) The request for a postponement must state in detail the reasons why a postponement is necessary. If a request is based upon the absence of witnesses, it must state what the substance of the testimony of the absent witnesses would be. No postponement will be granted if the adverse party or parties file with the examiner within 5 days after the service of the request a statement admitting that the witnesses on account of whose absence the postponement is desired would, if present, testify as stated in the request. If time does not permit the filing of such statement prior to the hearing, it may be made orally at the hearing.
(c) Only one postponement will be allowed to a party on account of the absence of witnesses unless the party requesting a further postponement shall at the time apply for an order to take the testimony of the alleged absent witness by deposition.