1. Log in to your Customer Portal;
2. On the Dashboard, click "Domains" from the left-side menu;
3. In the "Manage Domains" section, you will see all the domains in your account. Click your domain or the "More" button to see the "Domain Overview" tab, where more details and options for the selected domain will be displayed;
4. Under "Name Servers", click "Change" link to update your name servers.
   Alternatively, you may hover your mouse over the icons on the left, then click "Name Servers";
5. From here, you may either enter specific name servers or automatically point your domain to one of your hosting packages.
   • Select "Manually set my name servers";
   • Enter the nameservers (NS): ns1.site.pro
     ns2.site.pro
     ns3.site.pro
     ns4.site.pro
6. Once you have entered your name servers, click "Save Name Servers".

Source of information: hostgator.com.

Please be informed that after domain DNS renewal it may start working in up to 24 hours (usually it takes ~15 min). If the domain does not start working within 24 hours, please inform us by creating a support ticket.