Your question is very unclear as to what you are talking about.
If you have been sued for the threat, the plaintiff must file a request for dismissal with the court.
If you are suing someone for the threat, you must file that documents.
If no civil lawsuit has been filed, there is nothing to dismiss. The exposure to the lawsuit can be eliminated if the threatened person signs a release of claims.
If your question relates to some kind of criminal charge that was filed, you will need to look to the Criminal Defense practice area on this site and not the Lawsuits & Disputes practice area.
Good luck to you.
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