If five devices are already on the list and a subscribed user signs in on a sixth device, then this new device is added to the end of the list and the first device is removed. If a device meets requirements and a licensed user signs in on that device, it will be upgraded. The list of devices is chronological and cannot be manually modified.

Up to five devices can be upgraded for each user license. Is connected to the Internet again, the license will automatically renew assuming the device is still present on list of user devices. If a device is disconnected from the Internet until its current license expires, the operating system will revert to Windows 10 Pro. Devices that have been upgraded will attempt to acquire licenses every 30 days, and must be connected to the Internet to be successful. If you have feedback for TechNet Subscriber Support, check if it meet the following policies apply to acquisition and renewal of licenses on devices: Please remember to mark the replies as answers if they help. To the Internet again, the license will automatically renew. If a device is disconnected from the Internet until its current subscription expires, the operating system will revert to Windows 10 Pro or Windows 10 Pro Education.

The following policies apply to acquisition and renewal of licenses on devices: Subscription, when a user’s subscription expires or is transferred to another user, the Windows 10 Enterprise device reverts seamlessly to Windows 10 Pro edition (after a grace period of up to 90 days). When you purchase Windows 10 Enterprise E3 via a partner, it may Roll back to Windows 10 Pro at any time.

Windows sysinternals