37 CFR § 1.421 - Applicant for international application.
(a) Only residents or nationals of the United States of America may file international applications in the United States Receiving Office. If an international application does not include an applicant who is indicated as being a resident or national of the United States of America, and at least one applicant:
(1) Has indicated a residence or nationality in a PCT Contracting State, or
(2) Has no residence or nationality indicated, applicant will be so notified and, if the international application includes a fee amount equivalent to that required by § 1.445(a)(4), the international application will be forwarded for processing to the International Bureau acting as a Receiving Office (see also § 1.412(c)(6)).
(b) Although the United States Receiving Office will accept international applications filed by any applicant who is a resident or national of the United States of America for international processing, for the purposes of the designation of the United States, an international application will be accepted by the Patent and Trademark Office for the national stage only if the applicant is the inventor or other person as provided in § 1.422 or § 1.424. Joint inventors must jointly apply for an international application.
(c) A registered attorney or agent of the applicant may sign the international application Request and file the international application for the applicant. A separate power of attorney from each applicant may be required.
(d) Any indication of different applicants for the purpose of different Designated Offices must be shown on the Request portion of the international application.
(e) Requests for changes in the indications concerning the applicant, agent, or common representative of an international application shall be made in accordance with PCT Rule 92bis and may be required to be signed by all applicants.
(f) Requests for withdrawals of the international application, designations, priority claims, the Demand, or elections shall be made in accordance with PCT Rule 90bis and must be signed by all applicants. A separate power of attorney from the applicants will be required for the purposes of any request for a withdrawal in accordance with PCT Rule 90bis which is not signed by all applicants.