Where the mistake is in the description, claims or drawings, both the error and the correction must be such that it is immediately evident:
Regarding (i), the incorrect information must be objectively recognisable for a skilled person, using common general knowledge, from the originally-filed application documents (description, claims and drawings) taken by themselves.
Regarding (ii), the correction needs to be within the limits of what a skilled person would derive directly and unambiguously, using common general knowledge, and seen objectively and relative to the date of filing, from the originally-filed application documents.
In other words, the requirements of Art. 123(2) apply mutatis mutandis.
Evidence of what was common general knowledge on the date of filing may be furnished in any suitable form.
The priority documents cannot be used for the purposes mentioned under (i) and (ii) above (see G 3/89 and G 11/91).
Correction under Rule 139, second sentence, is of a strictly declaratory nature and establishes what a skilled person, using common general knowledge, would derive on the date of filing from the parts of a European patent application, seen as a whole, relating to the disclosure (see G 3/89 and G 11/91 mentioned above). Therefore, the complete replacement of the application documents (i.e. description, claims and drawings) by other documents is not possible (see G 2/95).
Some examples of allowable corrections:
On the other hand, the applicant/proprietor cannot rely on:
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/h_vi_2_2_1.htm
Date retrieved: 17 May 2021
18 references found.
Click X to load a reference inside the current page, click on the title to open in a new page.EPC Articles
EPC Implementing Rules
EPO Guidelines - A Formalities Examination
EPO Guidelines - C Procedureal Aspects of Substantive Examination
EPO Guidelines - H Amendments and Corrections
XGL H VI 2.2.2 Missing parts of description and missing drawings filed as corrections under Rule 139