1. Cancel authorization: If you are the owner of the seal, you can cancel or revoke the authorization of the relevant institutions or individuals to use the seal in writing. You can send a formal written notification letter to ensure that the recipient acknowledges receipt and understands your intention.

2. Proof of impartiality: You can contact the local notary office, law firm or impartiality to explain the legal effect of canceling the signature and seal. They can give you specific legal advice and help you complete the cancellation procedure.

3. Replace the signature seal: If you want to completely cancel the effectiveness of the previous signature seal, you can consider replacing the new signature seal and stop using the old one. The new signature seal can be a new design, words or other signs, representing your personal identity.