A European patent application or European patent may be amended in examination, opposition and limitation proceedings. With regard to amendments filed in such proceedings, there are a number of important aspects to consider. Firstly, amendments must be admissible, i.e. they must meet the requirements for being admitted into the proceedings (see H‑II, H‑III).
Secondly, amendments must be allowable, which means, in particular, that they must not:
Chapters H‑II and H‑III deal with the admissibility of amendments, while Chapters H‑IV and H‑V deal with their allowability. Chapter H‑VI is dedicated to the correction of errors.
Source: http://www.epo.org/law-practice/legal-texts/html/guidelines/e/h_i.htm
Date retrieved: 17 May 2021