(a) PATENT APPLICANT.-An applicant for a patent, any of whose claims has been twice rejected, may appeal from the decision of the primary examiner to the Patent Trial and Appeal Board, having once paid the fee for such appeal. (b) PATENT OWNER.-A patent owner in a reexamination may appeal from the final rejection of any claim by the primary examiner to the Patent Trial and Appeal Board, having once paid the fee for such appeal. 35 U.S.C. § 134 July 19, 1952, ch. 950, 66 Stat. 801; Pub. L. 98-622
(a)Filing and service. Within 20 days after the service of the complaint (within 10 days in a proceeding under section 4(d) of the Perishable Agricultural Commodities Act, 1930), or such other time as may be specified therein, the respondent shall file with the Hearing Clerk an answer signed by the respondent or the attorney of record in the proceeding. The attorney may file an appearance of record prior to or simultaneously with the filing of the answer. The answer shall be served upon the complainant