Administrative Instructions under the Patent Cooperation Treaty
Rectifications of Obvious Mistakes under Rule 91
(a) Where the International Bureau authorizes a rectification under Rule 91, it shall:
(ii) indelibly mark, in the middle of the bottom margin of each replacement sheet, the words “RECTIFIED SHEET (RULE 91)” or their equivalent in the language of publication of the international application;
(iv) keep in its files a copy of the letter containing the rectification or, when the rectification is contained in a replacement sheet, the replaced sheet, a copy of the letter accompanying the replacement sheet, and a copy of the replacement sheet.
(c) Where the International Bureau authorizes or refuses to authorize the rectification of an obvious mistake under Rule 91, it shall notify the applicant, the International Searching Authority, where a demand has been made, the International Preliminary Examining Authority, as well as the designated or elected Offices accordingly and, where the International Bureau refuses to authorize a rectification, the notification shall also include the reasons for the refusal.