prighi61 wrote:
You have to use an SQL tool like SQL Server Management Studio to do it manually (use the "Edit the first 300 records" feature or write a Delete SQL script).
To do it programmatically then it depends by the software environment you would use.
Prighi61 is right as to the changing or removing them.
However if your concerned about your users changing them, you might want to try this: Configuration, General Settings, Users Permissions, Users may alter ticket state. That should keep their mitts of those types.
Or this: Same area, Auto assign, Other exclusions - Add exclusion. This might allow you to exclude ticket types here. This would prevent the ticket types from being auto-assigned as I understand it.