Intellectual Property Code
Section 63. Notice of Hearing. - Upon filing of a petition for cancellation, the Director of Legal Affairs shall forthwith serve notice of the filing thereof upon the patentee and all persons having grants or licenses, or any other right, title or interest in and to the patent and the invention covered thereby, as appears of record in the Office, and of notice of the date of hearing thereon on such persons and the petitioner. Notice of the filing of the petition shall be published in the IPO Gazette. (Sec. 31, R.A. No. 165a)