37 C.F.R. § 2.174
Whenever Office records clearly disclose a material mistake in a registration, incurred through the fault of the Office, the Office will issue a certificate of correction stating the fact and nature of the mistake, signed by the Director or by an employee designated by the Director, without charge. Thereafter, the corrected certificate shall have the same effect as if it had been originally issued in the corrected form. In the discretion of the Director, the Office may issue a new certificate of registration without charge.
37 C.F.R. §2.174
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.