Actions that were added at the device or monitor level can be removed by selecting the action in the Actions dialog of the Device or Monitor Properties, and clicking Remove. This does not effect any other item in the database.
If you have assigned action policies to your devices, you can remove the action from the policy itself.
To remove an action from the database completely, you must access the Action Library, select the action and click Delete. When an action is removed from the Library, it is also removed from all items configured to use that action.