D.C. Mun. Regs. tit. 17, r. 17-1721
A respondent may be represented by an attorney who is an active member of the District of Columbia Bar.
In a particular case, the Director or the Hearing Examiner may permit an attorney who is an active member of the Bar of another jurisdiction of the United States to represent a respondent.
If it appears to the Director or a Hearing Examiner 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 Director or Hearing Examiner 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.
An attorney shall not participate in a representative capacity in any hearing conducted by a Hearing Examiner until the attorney submits to the Hearing Examiner a signed statement containing the attorney's name, street address, telephone number, and bar number.
An attorney authorized to appear pursuant to this section may sign any paper required or permitted to be filed by this chapter.
D.C. Mun. Regs. tit. 17, r. 17-1721