Editing DNS Records
From Lunarpages Web Hosting Wiki
Q: Can I edit my own DNS records?
A: Unfortunately, you cannot do this. We have to change records for you unless it happens to be an MX entry. If it is a single MX record, you can change it in cPanel under Mail, Modify Mail Exchanger (MX Entry). But for multiple MX records or for A's and CNAMES you would have to contact our Helpdesk by e-mailing email@example.com.
If you are simply trying to change Name Server however, you are able to do that yourself - you simply have to login at your registrars where you have the domain registered and use the control panel they provide to do this.