If someone infringes on your trademark, you typically start by sending them a cease and desist letter, requesting they stop using your mark. Sometimes, infringers stop once they realize they're violating your rights.

However, if they refuse to comply, you may need to consider legal action. Consulting with an attorney experienced in trademark law is advisable to determine the best course of action.

Successful trademark infringement lawsuits often involve:
1. Ownership of a valid mark, typically presumed with a federal trademark registration.
2. Unauthorized use of the mark in connection with goods or services.
3. Usage likely to confuse consumers.

Yes, it's possible to amend a trademark application, but the process and associated fees depend on when the changes are made. Changes before the trademark is published in the Official Gazette can be requested through your Trademark Engine account, with additional fees to both Trademark Engine and the USPTO potentially applicable.

For changes after publication, a Post-Publication Amendment is generally required, which Trademark Engine can assist with.

However, significant amendments, such as broadening the scope of description or adding international categories, may necessitate filing a new application with additional fees. Clerical errors, though, are usually straightforward to correct and typically won't impact the application's status or require a new filing.

Trademark dilution is another theory of infringement, distinct from consumer confusion. It occurs when a trademark owner asserts that their famous mark is being weakened in its distinctiveness or reputation by the use of a similar mark, even if there's no likelihood of confusion. This weakening can happen through "blurring," where the distinctiveness of the mark is diminished, or "tarnishing," where the mark's image is connected to something objectionable or negative.

A Cease and Desist Letter serves as a formal notice to an alleged infringer, informing them of the infringement and demanding that they stop the infringing activity within a specified timeframe. Often, receiving such a letter prompts the alleged infringer to voluntarily cease their activities, resolving the matter without further legal action. However, if the recipient disregards the letter and continues infringing, the letter can serve as evidence of willful infringement in any subsequent lawsuit, potentially resulting in additional damages. It's important to note that a cease and desist letter does not hold the same legal weight as an order issued by a court; to obtain such an order, legal action must be pursued and approved by a judge.

In such a scenario, the determination of trademark rights often hinges on the concept of priority. To successfully assert a trademark infringement claim in court, the plaintiff must demonstrate ownership of a valid mark and priority, meaning that their rights in the mark precede those of the alleged infringer. If the individual claiming prior use of the mark can substantiate their assertion with evidence of use predating the registration with the USPTO, they may retain the right to continue using the mark as they were prior to the registration.

It's crucial to recognize that while federal trademark registration on the Principal Register carries presumptions of validity, ownership, and exclusive nationwide use, these presumptions can be challenged and rebutted in legal proceedings. Therefore, if someone else used a similar mark before the registration, their prior use may grant them certain rights, though potentially limited in scope, such as geographical limitations or restrictions on expanding the use of the mark to additional goods or services.