Thanks for your response. Customer has two different ISE cluster with different versions for some specific reason. Few of the policies are also different on one of the ISE clusters. All the users were registered on one ISE node and now customer wants same level of BYOD access without re-registration of the endpoints when user moves to different ISE cluster. Backup and restore option is not feasible for us. I tried to export endpoint database but it does not export all the information like user mapping.
note: Customer is not doing complete BYOD. We are only registering the devices and placing it in registered endpoint group