What must an applicant or registrant file in case of their own mistakes in paperwork?

The correct answer involves the necessity for an applicant or registrant to file a corrective assignment when they identify mistakes in their paperwork. A corrective assignment is a legal document that allows the entity to amend previously submitted filings. This could involve correcting errors relating to ownership, details about the mark, or any other inaccuracies that may have arisen in their trademark application or registration.

This option directly addresses the need for a formal process to rectify mistakes, ensuring that the trademark records maintained by the USPTO accurately reflect the status and ownership of the trademark. It is crucial for maintaining the integrity of the trademark system and protecting the rights of the parties involved.

The other options do not apply to correcting mistakes in trademark paperwork. Informal notifications are not formal enough to rectify errors and would not provide the necessary legal effect. Legal appeals are utilized to challenge decisions made by the USPTO, rather than amend mistakes. Lastly, a license transfer pertains to transferring rights to use a trademark but is not relevant to correcting mistakes in submissions. Thus, the approach to rectify paperwork mistakes is best served through a corrective assignment.