PCT Receiving Office Guidelines
Chapter XV: Rectification of Obvious Mistakes Under Rule 91
Invitation to the Applicant to Request Authorization of Rectification
308. If the receiving Office discovers what appears to be an obvious mistake in the international application or any other paper submitted by the applicant, it may invite (Form PCT/RO/108) the applicant to submit a request for rectification to the Authority competent to authorize the rectification (Rules 91.1(b) and 91.2).