Search is your friend. This has been covered before.http://forum.osticket.com/d/discussion//delete-all-tickets-from-ostickethttp://forum.osticket.com/d/discussion//deleting-tickets-in-databasehttp://forum.osticket.com/d/discussion//delete-department-and-all-its-ticketshttp://forum.osticket.com/d/discussion//resolved-start-over-from-ticketid-1Short version is drop the info from the table(s) and then set AUTO_INCREMENT to 0.