According to rule 100 of the European Paten Convention (EPC) Implementing Regulations (IR) ,
(1)
Unless otherwise provided, the provisions relating to proceedings before the European Patent Office (EPO) department which has taken the decision impugned shall apply to appeal proceedings.
(2)
In the examination of the appeal, the EPO Board of Appeal shall invite the parties, as often as necessary, to file observations, within a period to be specified, on communications issued by itself or observations submitted by another party.