39 CFR §952.16

1. (a)Respondent may appear and be heard in person or by attorney. A Notice of Appearance must be filed by any attorney representing Respondent.
2. (b)An attorney may practice before the Postal Service in accordance with applicable rules issued by the Judicial Officer. See 39 CFR Part 951.
3. (c)When Respondent is represented by an attorney, all pleadings and other papers subsequent to the complaint shall be mailed to the attorney.
4. (d)Withdrawal by any attorney representing a party must be preceded by a motion to withdraw stating the reasons therefore, and shall be granted in the discretion of the presiding officer. If a successor attorney is not appointed at the same time, withdrawing counsel shall provide adequate contact information for Respondent.
5. (e)Parties must promptly file a notice of change of attorney.