To remove a student from a class, locate them on the Students tab, tap the "Action" icon, and select "Remove from class."
Removing the student from your class removes their work from the class library and reduces your class headcount. The account isn't deleted, though, and you still have access to their account and stories.
After a student is Removed, you then have the option to Delete their account and all associated data will be deleted.
Please note that Connected Parents will be unable to retrieve copies of student work from deleted accounts. They must do this before the account is deleted. Your Students page indicates the status of the Parent Connection, and whether they have taken a copy.
You can create a text archive of student data at any time prior to Deletion from your Class Settings. Please note that images are not part of the archive.