PCT Receiving Office Guidelines
Chapter XI: Fees
Notification Concerning Payment of Fees before the Date on Which They Are Due
258. The receiving Office, upon receipt of a (purported) international application, checks whether any payment of fees has been made and notifies the applicant accordingly (payment of all, or only part of, the prescribed fees or overpayment to be refunded). Where no or insufficient fees have been paid, the receiving Office may invite (Form PCT/RO/102) the applicant to pay the balance due within the applicable time limit(s) (Section 304).