You can use Rename Computers task to rename computers to FQDN format in ERA. You can use existing server task that came default with ERA installation. This task automatically rename synchronized computers located in Lost & found every hour. or create new, click Server Task > Rename computers > New.
Enter basic information about the task, such as the Name, Description (optional) and Task Type. The Task Type defines the settings and behavior of the task. Select the check box next to Run task immediately after finish to have the task run automatically after you click Finish.
Group name - select a Static or Dynamic Groups or create new a Static or Dynamic Group, where will be renamed computers.
Rename based on:
Resolution of name conflicts for computers already present in ERA (computer name must be unique) and those added via synchronization. Checks only apply to the names of computers outside the subtree being synchronized.
Review the configuration information displayed here and if it is ok, click Finish. The task is now created and ready to be used.