37 CFR 1.424: Assignee, obligated assignee, or person having sufficient proprietary interest as applicant in an international application.

(a) A person to whom the inventor has assigned or is under an obligation to assign the invention may be an applicant in an international application which designates the United States of America. A person who otherwise shows sufficient proprietary interest in the matter may be an applicant in an international application which designates the United States of America on proof of the pertinent facts and a showing that such action is appropriate to preserve the rights of the parties.

(b) Neither any showing required under paragraph (a) of this section nor documentary evidence of ownership or proprietary interest will be required or considered by the Office in the international stage, but will be required in the national stage in accordance with the conditions and requirements of § 1.46.