You have to be careful when unsharing a Class, as you don't want to unenroll any Enrollees unintentionally. Follow these steps to properly unshare a Class:
Go to the Class that you originally shared to unshare the Class
Click the "Shared" button, then deselect the Class
Click "Save" and the Class will be unshared
Unsharing the Wrong Way
If you get a notification like the one below, you are trying to unshare the wrong Class (the Class that is inheriting the characteristics of the Class being shared and NOT the Class that is being shared):
NOTE: If you click "Continue" here, you will UN-ENROLL all the listed enrollments! This CANNOT BE UNDONE!
If the Enrollee is not enrolled in another Class within the same Program, the Enrollee will be moved to the Unassigned List. If the Enrollee IS enrolled in another Class within the same Program, they will NOT show up on the Unassigned List.