c) Remittal to the department of first instance 

According to T 1843/09 (OJ 2013, 508) the prohibition of reformatio in peius as far as it entails a procedural limitation of the proprietor's liberty to change by way of amendments the scope of protection sought prevails "in principle" (G 4/93, OJ 1994, 875) until the final settlement of the opposition case and, therefore, also in any proceedings, including further appeal proceedings, subsequent to a remittal under Art. 111 EPC. The board went on to say that it is clear from G 1/99 that exceptions to the principle of the prohibition of reformatio in peius are a matter of equity in order to protect the non-appealing proprietor against procedural discrimination in circumstances where that prohibition would impair the legitimate defence of its patent. Therefore, exceptions are not limited to the situation specifically dealt with in G 1/99. Rather, the equity approach as taken by the Enlarged Board of Appeal covers, beyond an error of judgment by the opposition division, any change of the factual and/or legal basis on which limitations have been made by the proprietor prior to the appeal by the opponent as the sole appellant, provided the proprietor would be prevented by the prohibition on reformatio in peius from adequately defending its patent against new facts and objections introduced into the proceedings at the appeal stage.

In T 24/13, the appellant had asserted that a remittal under Art. 111 EPC would also put it at a disadvantage as the proprietor might possibly be granted a broader patent. The board disagreed because the prohibition on reformatio en peius applied equally in opposition proceedings resumed after such remittal (see T 1843/09, OJ 2013, 508; T 1033/08).