How to change IP address on an AIX machine without making GPFS go down?

If I change the IP address, my new address is not showing up from neither
mmlscluster nor mmlsconfig, only the old one. And since that is the
situation after IP change, GPFS will not mount the GPFS file systems. The
same happens if I change the hostname.

Sure it is possible to fool GPFS with an IP alias, I have tried, but it is
for sure more simple way of doing it? mmchcluster, mmchconfig or something?
Without dropping existing GPFS file system?

Thanks!

ArneS