You can access various options to change ticket property. Go to ticket detail view page from left side panel in last tab you can access below Ticket Options.
Assigned to : You can select agent from drop-down whom you would to like assign or reassigned ticket
SLA Plan : Option to change SLA time as per your requirement
Priority : You can change ticket priority anytime
Help Topic : Move / Transfer ticket from one helptopic to another
Status : To change the ticket status
To update any properties , you need to select desire option from drop-down and click "Update" button at end.