37 CFR 2.135: Abandonment of application or mark.

After the commencement of an opposition, concurrent use, or interference proceeding, if the applicant files a written abandonment of the application or of the mark without the written consent of every adverse party to the proceeding, judgment shall be entered against the applicant. 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.