Firstly, I want hide the 'department' from the Help Center. I have try this by unchecking the "Display in Help Center" of all departments. The ticket created by the user then will go to the default department. Now the user can still view the ticket from the Help Center. But when I as a agent move the ticket to the desired department, the user cannot view the ticket anymore from the Help Center. I just want the agent is the only one can choose which ticket belongs to which department, not the user. At the same time, I want the user can still view their created ticket in the Help Center even though the agent have move the ticket to the other department.