On an AE managed device (i.e. AE-DO), you can unenroll or delete the device from the web-console and the MobiControl device agent will then prompt you to input a different enrollment ID/URL so that it can be enrolled again to the same or a different MobiControl server.

You are not supposed to uninstall the MobiControl device agent app and keep the data/app on the device without any more protection from the original MDM installed right after the previous factory reset that gets the device in AE-DO mode.  This is, by definition, the expected behaviour for an AE-DO device.   

Hello Friend,

AE will provision the device in a different way, so whenever it is provisioned in this way it will only work for the chosen MDM. You can deprovision and provision again in another environment in the same MDM or another profile in the same environment.

If this phone is in operation and you need to make releases for the end user I advise you to keep the locks for Android to work properly and release in the feature control to add google accounts, this way the end user can put his google account on the device. I do not recommend this type of action because it brings damage to support and operation. However in some cases there is a request for release and we have to act, keep the device provisioned with the rules but release more functions for the end user if this is your case.

AE whenever you remove the application catalog profile from the device or remove the device from the environment it will lose any configuration and installation and this will always happen.