37 CFR 1.455 - Representation in international applications.
(a) Applicants of international applications may be represented by attorneys or agents registered to practice before the United States Patent and Trademark Office or by an applicant appointed as a common representative (PCT Art. 49, Rules 4.8 and 90 and § 11.9). If applicants have not appointed an attorney or agent or one of the applicants to represent them, and there is more than one applicant, the applicant first named in the request and who is entitled to file in the U.S. Receiving Office shall be considered to be the common representative of all the applicants. An attorney or agent having the right to practice before a national office with which an international application is filed and for which the United States is an International Searching Authority or International Preliminary Examining Authority may be appointed to represent the applicants in the international application before that authority. An attorney or agent may appoint an associate attorney or agent who shall also then be of record (PCT Rule 90.1(d)). The appointment of an attorney or agent, or of a common representative, revokes any earlier appointment unless otherwise indicated (PCT Rule 90.6 (b) and (c)).
(b) Appointment of an agent, attorney or common representative (PCT Rule 4.8) must be effected either in the Request form, signed by applicant, in the Demand form, signed by applicant, or in a separate power of attorney submitted either to the United States Receiving Office or to the International Bureau.
(c) Powers of attorney and revocations thereof should be submitted to the United States Receiving Office until the issuance of the international search report.
(d) The addressee for correspondence will be as indicated in section 108 of the Administrative Instructions.