Mismanage your company trademarks and you lose them. For example, if you stop using a trademark for three years, the law assumes you've abandoned the mark and it loses legal protection. Another way to kill it is to ignore requests for paperwork or information from the U.S. Patent and Trademark Office when you're filing a trademark petition. Once you abandon a mark, another company can try to claim it. However, you may be able to revive the dead trademark yourself.
You Haven't Abandoned It
To keep your mark alive after you stop using it, you have to show you haven't abandoned it. Suppose someone else files to revive your mark and you take them to court. If you can show you were only waiting for regulators to approve your trademarked line, that's evidence your trademark was never dead. You can't do this by suddenly using the mark after someone else claims it. You have to prove you were using it or preparing to use it during the three-year dead zone.
Revive Your Application
If you miss a filing deadline for your application paperwork, the Patent and Trademark Office will notify you that your application is dead. After the office sends out the rejection notification, you have two months to reapply. All you have to do to revive your submission is fill out a petition on the USPTO website.
If some other company has let its trademark die, you can revive it by filing your own claim with USPTO. You have to meet all the usual trademark-filing standards. Even if you do, the original holder may file objections with USPTO or sue you in court, even if the company hasn't used the mark in years. The more the mark is remembered and associated with the previous owner, the tougher it will be to prove you're reviving the dead.