In T 1561/05 the board held that in the context of inter partes proceedings, the patent proprietor and the opponent were also parties to the re-establishment proceedings. The party contesting the request has an unlimited right to be heard under Art. 113 EPC 1973.
In T 552/02 the board held that the response to be given to the application for re-establishment was of the utmost importance for the respondents, as it affected the actual admissibility of the appeal and hence the reviewability of the opposition division's decision to revoke the patent in suit. From this the board deduced that it would be a breach of Art. 113(1) EPC 1973 to take a decision concerning the interests not only of the appellants but also of the respondents without giving the latter an opportunity to present comments.