At naturalForms, you can manage the registered devices on your account. The number of active devices that you can have is limited by the number of subscriptions you have purchased for your account.
Devices are Added automatically to your account as soon as a user signs into the naturalForms app on a device.
Devices can then be removed from your account through the Delete 
icon. Once a device is deleted, you will free up one of your subscription licenses to be used on a new device.