To update name sever from client area , fallow bellow steps
Log in to your client area
Click on the services ---> Click on Domains
Click on the domain name you want to update.
Scroll down to the " Name server " section.
Enter the new nameservers in the "Nameserver 1" and "Nameserver 2" fields.
Click on the "Save Changes" button to apply the changes.
Once you have updated your domain name server , it may take some time for the changes to propagate and for your website to be accessible using the new nameservers. This propagation period can take anywhere from a few hours to up to 48 hours, depending on the DNS caching policies of various internet service providers.