Rule 22³¹
Registration of transfers

(1) The transfer of a European patent application shall be recorded in the European Patent Register at the request of an interested party, upon production of documents providing evidence of such transfer. 

(2) The request shall not be deemed to have been filed until an administrative fee has been paid. It may be rejected only if paragraph 1 has not been complied with.

(3) A transfer shall have effect vis-à-vis the European Patent Office only at the date when and to the extent that the documents referred to in paragraph 1 have been produced.