(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.

(a) The appointment of an agent shall be effected by the applicant signing the request, the demand, or a separate power of attorney. Where there are two or more applicants, the appointment of a common agent or common representative shall be effected by each applicant signing, at his choice, the request, the demand or a separate power of attorney.
(b) Subject to Rule 90.5, a separate power of attorney shall be submitted to either the receiving Office or the International Bureau, provided that, where a power of attorney appoints an agent under Rule 90.1(b), (b-bis), (c), or (d)(ii), it shall be submitted to the International Searching Authority, the Authority specified for supplementary search or the International Preliminary Examining Authority, as the case may be.
(c) If the separate power of attorney is not signed, or if the required separate power of attorney is missing, or if the indication of the name or address of the appointed person does not comply with Rule 4.4, the power of attorney shall be considered nonexistent unless the defect is corrected.
(d) Subject to paragraph (e), any receiving Office, any International Searching Authority, any Authority competent to carry out supplementary searches, any International Preliminary Examining Authority and the International Bureau may waive the requirement under paragraph (b) that a separate power of attorney be submitted to it, in which case paragraph (c) shall not apply.
(e) Where the agent or the common representative submits any notice of withdrawal referred to in Rules 90bis.1 to 90bis.4, the requirement under paragraph (b) for a separate power of attorney shall not be waived under paragraph (d).

(a) Appointment of an agent in relation to a particular international application may be effected by referring in the request, the demand, or a separate notice to an existing separate power of attorney appointing that agent to represent the applicant in relation to any international application which may be filed by that applicant (i.e., a “general power of attorney”), provided that:

(i) the general power of attorney has been deposited in accordance with paragraph (b), and
(ii) a copy of it is attached to the request, the demand or the separate notice, as the case may be; that copy need not be signed.

(b) The general power of attorney shall be deposited with the receiving Office, provided that, where it appoints an agent under Rule 90.1(b), (c), or (d)(ii), it shall be deposited with the International Searching Authority, the Authority specified for supplementary search or the International Preliminary Examining Authority, as the case may be.
(c) Any receiving Office, any International Searching Authority, any Authority competent to carry out supplementary searches and any International Preliminary Examining Authority may waive the requirement under paragraph (a)(ii) that a copy of the general power of attorney is attached to the request, the demand or the separate notice, as the case may be.
(d) Notwithstanding paragraph (c), where the agent submits any notice of withdrawal referred to in Rules 90bis.1 to 90bis.4 to the receiving Office, the Authority specified for supplementary search, the International Preliminary Examining Authority or the International Bureau, as the case may be, a copy of the general power of attorney shall be submitted to that Office, Authority or Bureau.