Edit the subdomain related file under /var/cpanel/userdata/<username>/ directory.
# vi /var/cpanel/userdata/<username>/subdomain.domain.tld
Change the value of “IP” to a dedicated IP and save the file
Rebuild the Apache configuration for the changes to take affect
# /scripts/rebuildhttpdconf
Restart the Apache webserver
# service httpd restart
Add dedicated IP and sub-domain in the /etc/domainips
dedicatedIP: subdomain.domain.tld
Save the file and rebuild the IP pool
# /scripts/rebuildippool
Edit the DNS zone file, add an ‘A’ record for the sub-domain to point to the new IP
# vi /var/named/domain.tld.db
Save the file and restart the ‘named’ service
# service named restart
