37 C.F.R. § 2.131
If, during an inter partes proceeding involving an application under section 1 or 44 of the Act, facts are disclosed which appear to render the mark unregistrable, but such matter has not been tried under the pleadings as filed by the parties or as they might be deemed to be amended under Rule 15(b) of the Federal Rules of Civil Procedure to conform to the evidence, the Trademark Trial and Appeal Board, in lieu of determining the matter in the decision on the proceeding, may remand the application to the trademark examining attorney for reexamination in the event the applicant ultimately prevails in the inter partes proceeding. Upon remand, the trademark examining attorney shall reexamine the application in light of the matter referenced by the Board. If, upon reexamination, the trademark examining attorney finally refuses registration to the applicant, an appeal may be taken as provided by §§ 2.141 and 2.142 .
37 C.F.R. §2.131
Part 3 pertaining to both patents and trademarks is placed in the grouping pertaining to patents regulations.
Part 4 is placed in the separate grouping of parts pertaining to patents regulations.
Part 5 is placed in the separate grouping of parts pertaining to patents regulations.