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Head to the User Admin page
Press Edit on the user you want to change/remove the subscriptions from
Once you have selected the user you want to change/remove the subscription from you can you unselect the subscription from the User Access and it will prompt you with a popup asking if you want to keep this seat open for someone else. if you want to keep this subscription you can click keep open, and if not you can click remove seat, which removes the subscription entirely.
The prompt that will pop up:
After you have decided what to do with the subscription press the save button.
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