The subnet of our company had been changed and due to this the netback up appliance is not working. currently finding challenges to login. Is there any other was to access the appliance in other to change the IP address on the appliance.
You can use IPMI to get access to the appliance.
Open a case to support. You cannot change the management IP of an appliance.
If it is a flex appliance, the IP is configured in many configuration files. Changing just the IP of the appliance will not work