You certainlu can change the IP's without having to erase the system. Remember this is only a Management plane change, not Data Plane, so you can do this without disrupting your server traffic.
Here's how I'd suggest you do it:
1. Log into the Console of each FI with admin account.
2. Find out which FI is the secondary by issuing:
show cluster state
3. From the secondary FI console session issue:
scope fabric-interconnect [a/b]
4. Set the new IP parameters with:
set out-of-band ip [New-IP-Address] netmask [New-Netmak] gw [New-Gateway]
commit-buffer
*Note: If the subnet mask and/or Gateway aren't changing, you can omit them from the command above.
*At this stage you should be able to ping the new IP addresses assuming the upstream Management interface are setup correctly and assigned to the correct VLAN
5. Repeat for the Primary fabric interconnect from its console session.
6. Set the new VIP by issuing:
scope system
set virtual-ip x.x.x.x
commit-buffer
7. Test connectivity to each IP & VIP.
8. If you have any issues you should be able to use the console session to correct any mistakes without any service interuption other than UCSM access.
Regards,
Robert
