Rule 78¹⁰⁹
Procedure where the proprietor of the patent is not entitled

(1) If a third party provides evidence, during opposition proceedings or during the opposition period, that he has instituted proceedings against the proprietor of the European patent, seeking a decision within the meaning of Article 61, paragraph 1, opposition proceedings shall be stayed unless the third party communicates to the European Patent Office in writing his consent to the continuation of such proceedings. Such consent shall be irrevocable. However, proceedings shall not be stayed until the Opposition Division has deemed the opposition admissible. Rule 14, paragraphs 2 to Rule 14, paragraphs 4, shall apply mutatis mutandis.

(2) Where a third party has, in accordance with Article 99, paragraph 4, replaced the previous proprietor for one or some of the designated Contracting States, the patent as maintained in opposition proceedings may, for these States, contain claims, a description and drawings different from those for the other designated States.