After a trademark is declared invalid, it can no longer be used. Article 44 of the Trademark Law: If a registered trademark violates the provisions of Articles 10, 11 and 12 of this Law, or is registered by deception or other improper means, the Trademark Office shall declare the registered trademark invalid; Other units or individuals may request the Trademark Review and Adjudication Board to declare the registered trademark invalid. Procedure for an individual to request the invalidation of a registered trademark 1. Where any other entity or individual requests the Trademark Review and Adjudication Board to declare the registered trademark invalid, it shall apply to the Trademark Review and Adjudication Board; 2. After receiving the application, the Trademark Review and Adjudication Board shall notify the relevant parties in writing, file a reply within a time limit, and may handle the business of invalid trademark reply; 3. The Trademark Review and Adjudication Board shall decide to maintain the registered trademark or declare it invalid within 9 months, and notify the parties in writing. There are special circumstances need to extend the time limit, approved by the administrative department for Industry and Commerce of the State Council, can be extended for 3 months; 4. If a party refuses to accept the ruling of the Trademark Review and Adjudication Board, he may bring a lawsuit to the people's court within 30 days from the date of receiving the notice; After accepting the lawsuit, the people's court shall notify the other party in the trademark review and adjudication procedure to participate in the lawsuit as a third party.