Unregister Options:
This operation may also remove managed resources linked to the host such as virtual machines and DNS records. Change the setting "Delete Host upon Unregister" to false on the settings page to prevent this.
Unregister the host as a subscription consumer. Provisioning and configuration information is preserved. This option is disabled because the setting "Delete Host upon unregister" is set.
Completely deletes the host including VM and disks, and removes all reporting, provisioning, and configuration information.