In T 362/02 the opposition division had revoked the patent for the sole reason that the appellant had not replied to a communication under Art. 101(2) EPC 1973 inviting him to file observations. The board found that this decision was a substantial procedural violation because the EPC did not provide any sanction for a party's failure to reply to a communication under Art. 101(2) EPC 1973. Further, revocation of a patent for mere failure to reply to a communication was contrary to the clear intention of the law, which required a proprietor to agree to the form in which a patent was granted or amended and to use clear and unambiguous words if he wished to abandon a patent.