37 C.F.R. § 2.68 : Patents, Trademarks, and Copyrights — UNITED STATES PATENT AND TRADEMARK OFFICE, DEPARTMENT OF COMMERCE — GENERAL — RULES OF PRACTICE IN TRADEMARK CASES —EXAMINATION OF APPLICATION AND ACTION BY APPLICANTS — Express abandonment (withdrawal) of application

(a) Written document required. An applicant may expressly abandon an application by filing a written request for abandonment or withdrawal of the application, signed by the applicant, someone with legal authority to bind the applicant ( e.g., a corporate officer or general partner of a partnership), or a practitioner qualified to practice under §11.14 of this chapter, in accordance with the requirements of §2.193(e)(2). A request for abandonment or withdrawal may not subsequently be withdrawn.
(b) Rights in the mark not affected. Except as provided in §2.135, the fact that an application has been expressly abandoned shall not affect any rights that the applicant may have in the mark set forth in the abandoned application in any proceeding before the Office.

37 C.F.R. §2.68

80 FR 2311, 1/16/2015