We can re-register the nameservers to a different ip's , if we need so. Here are the simple steps to re-register the nameservers from godaddy.com
1)login to godaddy.com
2)click on 'my domains'
3)select your domain name
4)unlock the domain by clicking the lock symbol.
5)then clilck on your domain name
6)navigate to host summary and click on 'edit'
7)insert your new ip assigned for the nameserver,save. you can edit the second nameserver to update the ip.
The 'whois' record will be changed to the new nameserver assigned. You can 'host' to the nameservers to check whether the ip's are updated.