§ 11.4 Authority to represent in other cases.
Primary source
Verbatim text below is from the Electronic Code of Federal Regulations (eCFR), a public-domain U.S. government work. Always verify the current version with the eCFR before relying on it for any legal matter.
Full Text
When an attorney acting in a representative capacity appears in person or signs a document submitted to the Government Accountability Office in connection with a matter other than one involving a payment to be made by the United States, his personal appearance or signature shall constitute a representation that he is authorized and qualified to represent the particular party in whose behalf he acts. In the case of representatives other than attorneys, a simple written declaration from the principal will be accepted as evidence of the authority of the representative to act on behalf of the principal.
This is legal information, not legal advice. Laws vary by jurisdiction and change frequently. Always verify current law with official sources and consult a licensed attorney in your jurisdiction for advice on your specific situation.