For a trademark registration to remain valid, you must file a Trademark Declaration of Continued Use with the U.S. Patent and Trademark Office ("USPTO") between the fifth and sixth year anniversaries following registration.
However, the USPTO allows a six-month grace period following the sixth anniversary date. During this period, you may submit the Continued Use form with additional filing fees. If a trademark owner does not file this form within the grace period, the USPTO will consider the mark abandoned.