37 CFR 1.452 - Restoration of right of priority.
(a) If the international application has an international filing date which is later than the expiration of the priority period as defined by PCT Rule 2.4 but within two months from the expiration of the priority period, the right of priority in the international application may be restored upon request if the delay in filing the international application within the priority period was unintentional.
(b) A request to restore the right of priority in an international application under paragraph (a) of this section must be filed not later than two months from the expiration of the priority period and must include:
(2) The petition fee as set forth in § 1.17(m); and
(3) A statement that the delay in filing the international application within the priority period was unintentional. The Director may require additional information where there is a question whether the delay was unintentional.
(c) If the applicant makes a request for early publication under PCT Article 21(2)(b), any requirement under paragraph (b) of this section filed after the technical preparations for international publication have been completed by the International Bureau shall be considered as not having been submitted in time.