is it expanded ?
if not you should be able to log in screenshot dhcp and lan settings, neetwork elements icp xnet config
change lan settings and reboot including internal switch
log in using new Ip , change dhcp scope to match new settings
check that network element is showing corretc Ip address
check icp xnet settings to make sure local pabx has correct Ip address
if sip ext have static entries they have to be changed statically
if you update dhcp properly anything using dhcp should be updated
if its expanded it has a second cpu and it gets a bit trickey
If I never did anything I'd never done before , I'd never do anything.....