Under Art. 123(1) EPC, a European patent application or a European patent may be amended in proceedings before the EPO, in accordance with the Implementing Regulations. R. 137(3) EPC is of particular relevance.
R. 137(3) EPC stipulates that no further amendment may be made without the consent of the examining division. Thus the applicant may amend only if the examiner consents to the amendments proposed. Giving the examining division this discretion is intended to ensure that the examination procedure is brought to a conclusion in as few actions as possible (Guidelines C-IV, 3). In exercising its discretion the examining division must consider all relevant factors; in particular, it must balance the applicant's interest in obtaining a patent which is legally valid and the EPO's interest in bringing the examination procedure to a close in an effective way (in accordance with the principles set out in G 7/93). Furthermore, the exercise of discretion under R. 137(3) EPC needs to be reasoned (Guidelines H-II, 2).
In giving or withholding such consent, the examining division has to exercise its discretion responsibly and in accordance with the principles as set out in the decision G 7/93 (OJ 1994, 775) which, although made in relation to amendments made in the pre-grant stage, are of general validity. The Enlarged Board pointed out that in the exercise of its discretion under R. 86(3) EPC (now R. 137(3) EPC), an examining division is required to consider all relevant factors which arise in a case. In particular, it must consider both the applicant's interest in obtaining a patent which is legally valid in all of the designated states, and the EPO's interest in bringing the examination procedure to a close by the issue of a decision to grant the patent, and must balance these interests against one another (T 1982/07). Once an examining division has exercised such discretion, a board of appeal should only overrule it if it comes to the conclusion either that the examining division did not exercise its discretion in accordance with the right principles or that it exercised its discretion in an unreasonable way and had thus exceeded the proper limit of its discretion (see T 237/96 with particular reference to G 7/93, OJ 1994, 775, T 182/88, OJ 1990, 287, T 937/09).
In T 937/09, the board held that, under the second sentence of R. 137(3) EPC (as adopted by decision of the Administrative Council of 7 December 2006; see 13th edition of the "European Patent Convention", European Patent Office, 2007), it was for the examining division to decide in a proper exercise of discretion whether to admit amendments to a European patent application after the first communication. In the board's view, this meant that the examining division had to admit amendments filed by the applicant together with the reply to a communication giving reasoned notice of a particular deficiency for the first time, if it could already have raised an objection to that deficiency in its first communication, and if the amendments could be regarded as an objectively suitable attempt to correct the deficiency.
In T 166/86 (OJ 1987, 372) the board held that under R. 86(3) EPC 1973, further amendments which included the submission of a separate set of claims for a given contracting state could only be made with the consent of the examining division (see Legal Advice No. 4/80, OJ 1980, 48). The examining division had to take the decision on whether to consent to the requested amendment after due assessment of the particular circumstances. In particular, this involved balancing the EPO's interest in the speedy completion of the proceedings against the applicant's interest in obtaining a patent which was legally valid in all the contracting states. The examining division would not be able to refuse its consent to an amendment if, for good reasons, the applicant was only at that late stage in a position to request the amendment, or if the requested amendment was obviously essential for him and to take it into account would not appreciably delay the grant procedure. In the board's view, the latter situation was the case here.
In T 640/91 (OJ 1994, 918) the board stated that the requirement in Art. 96(2) EPC 1973 that the examining division must invite the applicant to file his observations "as often as necessary" implicitly recognised that in certain circumstances the examining division would be legally obliged to invite further observations from the applicant before issuing a decision. Having regard to Art. 113(1) EPC 1973, there was a "necessary" legal obligation for an examining division to invite further observations from an applicant before issuing a decision adversely affecting him, where the division might be inclined to issue an immediate decision on the ground that he had shown lack of good faith in his previous observations. The board pointed out, moreover, that it was in principle not the function of an examining division to assess either the degree of collaboration from applicants or their good faith when deciding whether or not to invite further observations in the exercise of its discretion under Art. 96(2) EPC 1973. The exercise of this discretion depended primarily upon whether or not there was a reasonable prospect that such an invitation could lead to the grant of a patent (see also T 855/90, in which the board found that the examining division had exercised its discretion unreasonably).
In T 229/93 the board found that in the circumstances of the case at issue the examining division should have considered refusing to consent to the amendments pursuant to R. 86(3) EPC 1973, since the filing of such amendments after the expiry of the time limit for answering the first communication of the examining division in the form of a completely retyped description was contrary to the requirement of procedural economy (see T 113/92).
In T 951/97 the board noted that whether or not consent was given was at the discretion of the examining division and depended on the facts of the individual case, on the nature of the grounds for seeking an amendment, and equally on the stage of the procedure. It was easier to secure an amendment at an earlier rather than at a later stage (see T 529/94 and T 76/89).