If the proprietor proposes amendments to the patent in reply to the grounds for opposition and the opposition division intends to maintain the patent in amended form pursuant to those grounds, other amendments not related to the grounds for opposition (e.g. clarifications), or corrections (H‑VI, 3.1), may be allowed provided that the patent thus amended still fulfils the requirements of the EPC and that the amendments are considered necessary and appropriate. In particular, if one part of a claim has been amended, it may be necessary or appropriate to amend other parts of the claim as well.
Moreover, where a "clarification" can be considered as a limitation of the claim, it would be admissible under Rule 80 and could form the basis for maintaining the patent in amended form, provided the other requirements of the EPC are also met by the amended text (with the exception of unity of invention – G 1/91). If the division is of the opinion that such a limiting clarification is not necessary, it should needs to consider that the practice of interpreting a claim in a contracting state may be quite different from that of the EPO, and hence the patentee may see a need for such a limiting clarification.
Such amendments, however, should are not be proposed by the opposition division and they can only be taken into consideration up to the pronouncement of the decision (in oral proceedings) or until the date the decision is handed over to the EPO's internal postal service for transmittal to the parties (in written proceedings) (see G 12/91).
If an otherwise allowable request for maintenance of the opposed patent either as granted or in amended form has been submitted, the following amendments should are not be allowed:
In the absence of any amendments submitted by the patent proprietor with a view to meeting the grounds for opposition, there is no possibility to make any other amendments (see for example T 223/97). Publication errors and exceptionally formatting/editing errors may however be corrected (see H‑VI, 4).