With a Flex classroom subscription, you are able to re-use student licenses multiple times throughout your subscription period. This would allow for you to assign the license to a student, and if perchance the student is no longer enrolled in your class, you can have the account reset and reassign it to another student. Our standard Student Account licenses do not allow for accounts to be reset.
Flex subscriptions are available as part of our custom plans. 

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How to use my Flex subscription?