Pleadings in a cancellation proceeding may be amended in the same manner and to the same extent as in a civil action in a United States district court.
37 C.F.R. §2.115
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.