EXFO FG-750 - Manual (Page 282)

Maintenance
268 FG-750
Replacing an RTU (managed by EMS)
8. Perform Recovery Configuration:
8a. Click the Detach from EMS button.
8b. Click the Recovery Configuration button.
8c. Enter the Old MAC Address (previously noted in step 2) in the
Recovery text box and click the recover button. The RTU will be
restarted.
9. On EMS web UI, select the RTU and then clear the Offline check box.
10. After completion of successful recovery, check the RTU status on EMS;
it should be in Not connected and Synchronized state.