37 CFR § 2.134 - Surrender or voluntary cancellation of registration.
(a) After the commencement of a cancellation proceeding, if the respondent applies for cancellation of the involved registration under section 7(e) of the Act of 1946 without the written consent of every adverse party to the proceeding, judgment shall be entered against the respondent. The written consent of an adverse party may be signed by the adverse party or by the adverse party's attorney or other authorized representative.
(b) After the commencement of a cancellation proceeding, if it comes to the attention of the Trademark Trial and Appeal Board that the respondent has permitted its involved registration to be cancelled under section 8 or section 71 of the Act of 1946, or has failed to renew its involved registration under section 9 of the Act of 1946, or has allowed its registered extension of protection to expire under section 70(b) of the Act of 1946, an order may be issued allowing respondent until a set time, not less than fifteen days, in which to show cause why such cancellation, failure to renew, or expiration should not be deemed to be the equivalent of a cancellation by request of respondent without the consent of the adverse party and should not result in entry of judgment against respondent as provided by paragraph (a) of this section. In the absence of a showing of good and sufficient cause, judgment may be entered against respondent as provided by paragraph (a) of this section.