(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