The assignee for an existing ticket can be changed by Support Supervisors and EDD Shop Managers.
To change the assignee, go to the Tickets admin screen. Click on a ticket. In the Stakeholders meta box, select a new “Support Staff” member to assign this ticket to. Click “Update Ticket” to save your changes.
The new assignee (support staff member) will get an email notification letting them know that they have been assigned to this ticket (unless you disabled “New Assignment” email notifications in the plugin settings).