37 C.F.R. § 1.144 Petition from requirement for restriction.
Title 37 - Patents, Trademarks, and Copyrights
After a final requirement for restriction, the applicant, in addition to making any reply due on the remainder of the action, may petition the Director to review the requirement. Petition may be deferred until after final action on or allowance of claims to the invention elected, but must be filed not later than appeal. A petition will not be considered if reconsideration of the requirement was not requested (see §1.181). [62 FR 53195, Oct. 10, 1997]
Title 37: Patents, Trademarks, and Copyrights
PART 1—RULES OF PRACTICE IN PATENT CASES
Subpart B—National Processing Provisions
Joinder of Inventions in One Application; Restriction
§ 1.144 Petition from requirement for restriction.

