Why did my ticket status change to ‘Assigned’?

A ticket will go from New to Assigned for one reason only, a SEND action was performed on the ticket.  However, there are multiple ways to perform a SEND action.  When you select a ticket or group of tickets, you can click on the SEND button.  Any ticket in the list that is currently in the NEW status, will change to the ASSIGNED status.  (A ticket that is already in the ASSIGNED status will be unaffected).  An AUTO SEND mobile is configured to perform the SEND action automatically, all tickets that get routed to an AUTOSEND mobile will automatically change from NEW to ASSIGNED.