If you’ve previously setup private nameservers and wish to change them to a different IP Address, here’s how you do this.
Change Custom Nameservers
Step 1: Login to your Client Area
Step 2: Click on Domains, then click on My Domains
Step 3: Click the Wrench icon next to the domain you wish to create Nameservers for
Step 4: Click Private Nameservers
Step 5: Input the name of the nameserver you wish to change, input the old, then new IP Address you want it to resolve to, click Save Changes
You will now have the same nameserver pointing to the new IP Address.