Yahoo!'s name servers must be listed as the primary and secondary name servers in order for Yahoo! to host your domain services properly.
A name server is similar to a telephone switchboard. It holds the information that tells the Internet where to find your web site and where to deliver your email. Name servers look something like this: yns1.yahoo.com.
When you change your name servers, the Internet looks to the new name server location to provide information related to your domain, including web site and email services. If you replace Yahoo!'s default name servers, Yahoo! will no longer be able to provide any services associated with your domain.
If you decide to cancel your Yahoo! service and use the domain services of a different provider, you will need to replace your Yahoo! name servers with those of your new provider. Please be sure to change your name servers before you cancel your Yahoo! service. After you cancel, you will no longer be able to access the Domain Control Panel to make name server changes.
Please note that changing your name servers does not cancel your Yahoo! plan. You will be billed for your service until you actively cancel your plan. Learn how to cancel your service.