Every class created on Turnitin has an end date that Turnitin administrators usually advise to make it at the end of the semester according to the nature of the assignment within that class to prevent duplicated students' accounts to be counted against our University's account limit.
Expired classes become read-only & can be accessible via the "Expired Classes" tab which is located on the right side of the screen on your instructor home page or "All Classes" tab:
→In case of the Master Class, a Section Class "class end date" is based on the end date of the Master Class itself. Once the Master Class is expired, the end date of each section class will update automatically.
To reactivate an expired class, then you just need to extend the end date of the class to a date that is in the future. You can do this by following the steps above & once you change the class end date to a future date, click the "Submit" button and your class will become active again.