(a) (1) The testimony of witnesses in inter partes cases may be submitted in the form of an affidavit or a declaration pursuant to § 2.20 and in conformance with the Federal Rules of Evidence, filed during the proffering party's testimony period, subject to the right of any adverse party to elect to take and bear the expense of oral cross-examination of that witness as provided under paragraph (c) of this section if such witness is within the jurisdiction of the United States, or conduct cross-examination
(a) An application subject to an opposition may not be amended in substance nor may a registration subject to a cancellation be amended or disclaimed in part, except with the consent of the other party or parties and the approval of the Trademark Trial and Appeal Board, or upon motion granted by the Board. (b) If, in an inter partes proceeding, the Trademark Trial and Appeal Board finds that a party whose application or registration is the subject of the proceeding is not entitled to registration