HA Connection lost after change Management IP address

It is expected to lose the HA setup after changing the management IP on a device that is part of HA. More importantly how was the management IP changed, I would do it in the following order: I hope this helps.

Reassign new mgmt. IP or change mgmt. IP to F5 that is in HA pair or environment

1. Create UCS file and download them to your PC from both units
2. Put the F5 in question in standby mode
3. Force it offline and KEEP it OFFLINE till you finish this process
4. Break the HA between those Units by resetting the trust on both units (they will read “standalone”)
5. Make sure that unit in question is and stays in “OFFLINE” state
6. Re-assign the new mgmt. IP and make sure you have access to it with the new IP
7. Make sure that unit in question is still and stays in “OFFLINE” state
8. Rebuild the HA with the new mgmt. IP from the active unit
9. Add the units/hostnames in the sync-failover group
10. Sync the units from the active “self” and check the “override config” check box
11. if successful they should be in sync
12. test the sync feature by creating a test http monitor on the active and sync it over
13. if that replicates it on the offline F5 it is working and you can delete the test monitor and sync
14. now you can release the unit in question from “OFFLINE” state
15. if you need to re-assign new IP on the active unit as well, perform failover so the initial active becomes standby and repeat the process above starting from step 3