D.C. Mun. Regs. tit. 17, r. 17-4106
A respondent appearing before a board at a hearing, or appealing a decision of an Administrative Law Judge (ALJ) before a board pursuant to § 4123, shall have the right to be represented by an attorney who is an active member of the District of Columbia Bar. The chairperson of the board shall give notice of that appearance to the Director and the Corporation Counsel.
If it appears to a board that the issues or facts in a matter before it are so complex that the interests of justice, saving time or facilitating the preparation of an adequate record would be served by the representation of a party by an attorney, the board may urge, but not require, that the party obtain the services of an attorney and may allow that party a reasonable period of time within which to do so.
No person may participate in a representative capacity in any hearing conducted by a board until the person delivers to the board a signed statement containing the person's name, street address, telephone number, and District of Columbia Bar number. The written statement of counsel shall be made a part of the record.
Any person authorized to appear pursuant to this section may sign any paper required or permitted either by this subtitle or the Act to be filed with a board.
D.C. Mun. Regs. tit. 17, r. 17-4106