In T 1178/04 (OJ 2008, 80) the opposition division had decidedthat the transfer of opponent status in the course of the opposition proceedings was valid. The board held that even if the transfer of the opponent status during the opposition proceedings was invalid, the appeal by the opponent was nevertheless admissible. The board explained that "party" simply meant someone who takes part in the proceedings before the EPO. If it was decided by the department of first instance that he was entitled to take part in the proceedings he remained a party even though this decision was later reversed on appeal; such a decision on appeal had the effect that he was no longer entitled to take part in the proceedings, but not that he had never been a party to the proceedings. His position could not change retrospectively from that of having been a party to that of never having been a party. After reviewing the evidence the board held that no valid transfer of the status of opponent had taken place. The only means of correcting this error was to set aside the decision of the opposition division as a whole. The opposition division was thus not bound by its previous decision. It was only bound by the ratio decidendi of the board's decision as regards the transfer of opposition status (see also T 1081/06).

In T 194/15 the board decided that the evidence submitted showed that the transfer of the business assets from Abbott to AbbVie took place before the opposition had been filed. Accordingly, the opposition filed by Abbott could no longer be transferred to AbbVie. As a consequence, the opposition proceedings were continued with the wrong party as opponent. Referring also to T 1178/04 and T 1982/09, the board decided to remit the case to the opposition division so that the proceedings could be conducted with the right party.