While trying to change main IP of server was facing issue

Where was getting message IPAddress is already an active IP

On checking around found the below solution which worked

Make sure that the IP address you’re trying to add has been removed from these files:

/etc/hosts
/etc/ips
/etc/mail_reverse_dns

If you happen to also be trying to add back the IP that was previous the primary IP address, you will also need to update this file:

/var/cpanel/mainip

Now could add the IP address back in server