D.C. Mun. Regs. tit. 18, r. 18-1026
If all parties waive their right to appear before the examiner and present evidence personally or by representative, it shall not be necessary for the examiner to give notice of and conduct an oral hearing.
A waiver of the right to appear shall be made in writing and filed with the examiner.
The waiver may be withdrawn by a party at any time prior to the mailing of the notice of decision in the case.
If the examiner believes that the personal appearance and testimony of the party or parties would assist him or her to ascertain the facts in issue in any proceeding, he or she may give notice of a time and place and conduct a hearing notwithstanding the filing of a written waiver as described in this section.
If a hearing is called and a party waiving oral hearing fails to appear before the examiner personally or by representative, the examiner shall make a record of the relevant written evidence, including applications, written statements, certificates, affidavits, reports, and other documents which were considered in connection with the proceeding, and shall consider such documents as all of the evidence in the proceeding and the decision shall be based on such documents as are made part of the record.
D.C. Mun. Regs. tit. 18, r. 18-1026