91.1 Rectification of Obvious Mistakes
(a) An obvious mistake in the international application or another document submitted by the applicant may be rectified in accordance with this Rule if the applicant so requests.
(b) The rectification of a mistake shall be subject to authorization by the “competent authority”, that is to say:
(i) in the case of a mistake in the request part of the international application or in a correction thereof—by the receiving Office;
(ii) in the case of a mistake in the description, claims or drawings or in a correction thereof, unless the International Preliminary Examining Authority is competent under item (iii)—by the International Searching Authority;
(iii) in the case of a mistake in the description, claims or drawings or in a correction thereof, or in an amendment under Article 19 or 34, where a demand for international preliminary examination has been made and has not been withdrawn and the date on which international preliminary examination shall start in accordance with Rule 69.1 has passed—by the International Preliminary Examining Authority;
(iv) in the case of a mistake in a document not referred to in items (i) to (iii) submitted to the receiving Office, the International Searching Authority, the International Preliminary Examining Authority or the International Bureau, other than a mistake in the abstract or in an amendment under Article 19—by that Office, Authority or Bureau, as the case may be.
(c) The competent authority shall authorize the rectification under this Rule of a mistake if, and only if, it is obvious to the competent authority that, as at the applicable date under paragraph (f), something else was intended than what appears in the document concerned and that nothing else could have been intended than the proposed rectification.
(d) In the case of a mistake in the description, claims or drawings or in a correction or amendment thereof, the competent authority shall, for the purposes of paragraph (c), only take into account the contents of the description, claims and drawings and, where applicable, the correction or amendment concerned.
(e) In the case of a mistake in the request part of the international application or a correction thereof, or in a document referred to in paragraph (b)(iv), the competent authority shall, for the purposes of paragraph (c), only take into account the contents of the international application itself and, where applicable, the correction concerned, or the document referred to in paragraph (b)(iv), together with any other document submitted with the request, correction or document, as the case may be, any priority document in respect of the international application that is available to the authority in accordance with the Administrative Instructions, and any other document contained in the authority’s international application file at the applicable date under paragraph (f).
(f) The applicable date for the purposes of paragraphs (c) and (e) shall be:
(i) in the case of a mistake in a part of the international application as filed—the international filing date;
(ii) in the case of a mistake in a document other than the international application as filed, including a mistake in a correction or an amendment of the international application—the date on which the document was submitted.
(g) A mistake shall not be rectifiable under this Rule if:
(i) the mistake lies in the omission of one or more entire elements of the international application referred to in Article 3(2) or one or more entire sheets of the international application;
(ii) the mistake is in the abstract;
(iii) the mistake is in an amendment under Article 19, unless the International Preliminary Examining Authority is competent to authorize the rectification of such mistake under paragraph (b)(iii); or
(iv) the mistake is in a priority claim or in a notice correcting or adding a priority claim under Rule 26bis.1(a), where the rectification of the mistake would cause a change in the priority date;
provided that this paragraph shall not affect the operation of Rules 20.4, 20.5, 26bis and 38.3.
(h) Where the receiving Office, the International Searching Authority, the International Preliminary Examining Authority or the International Bureau discovers what appears to be a rectifiable obvious mistake in the international application or another document, it may invite the applicant to request rectification under this Rule.
91.2 Requests for Rectification
A request for rectification under Rule 91.1 shall be submitted to the competent authority within 26 months from the priority date. It shall specify the mistake to be rectified and the proposed rectification, and may, at the option of the applicant, contain a brief explanation. Rule 26.4 shall apply mutatis mutandis as to the manner in which the proposed rectification shall be indicated.
91.3 Authorization and Effect of Rectifications
(a) The competent authority shall promptly decide whether to authorize or refuse to authorize a rectification under Rule 91.1 and shall promptly notify the applicant and the International Bureau of the authorization or refusal and, in the case of refusal, of the reasons therefor. The International Bureau shall proceed as provided for in the Administrative Instructions, including, as required, notifying the receiving Office, the International Searching Authority, the International Preliminary Examining Authority and the designated and elected Offices of the authorization or refusal.
(b) Where the rectification of an obvious mistake has been authorized under Rule 91.1, the document concerned shall be rectified in accordance with the Administrative Instructions.
(c) Where the rectification of an obvious mistake has been authorized, it shall be effective:
(i) in the case of a mistake in the international application as filed, from the international filing date;
(ii) in the case of a mistake in a document other than the international application as filed, including a mistake in a correction or an amendment of the international application, from the date on which that document was submitted.
(d) Where the competent authority refuses to authorize a rectification under Rule 91.1, the International Bureau shall, upon request submitted to it by the applicant within two months from the date of the refusal, and subject to the payment of a special fee whose amount shall be fixed in the Administrative Instructions, publish the request for rectification, the reasons for refusal by the authority and any further brief comments that may be submitted by the applicant, if possible together with the international application. A copy of the request, reasons and comments (if any) shall if possible be included in the communication under Article 20 where the international application is not published by virtue of Article 64(3).
(e) The rectification of an obvious mistake need not be taken into account by any designated Office in which the processing or examination of the international application has already started prior to the date on which that Office is notified under Rule 91.3(a) of the authorization of the rectification by the competent authority.
(f) A designated Office may disregard a rectification that was authorized under Rule 91.1 only if it finds that it would not have authorized the rectification under Rule 91.1 if it had been the competent authority, provided that no designated Office shall disregard any rectification that was authorized under Rule 91.1 without giving the applicant the opportunity to make observations, within a time limit which shall be reasonable under the circumstances, on the Office’s intention to disregard the rectification.