Buying Premium DNS does not move your domain onto it. The domain keeps whatever nameservers it had, and until those are changed the new zone is not consulted by anybody — the order is paid for and nothing is using it.
The service page says so when that is the case, and gives you the change in one step.
Point it
- Open Domains and choose the domain.
- Press Premium DNS under Manage. If the domain is not yet delegated to it, the tile says so.
- The Name servers form opens already filled in with the Premium DNS hostnames, in place of the ones the domain uses now. The row above shows what is being replaced.
- Press Update Name Servers.
The tile disappears once the delegation matches. If it is still there after a few minutes, the change has not been accepted — open it again and check the hostnames against the ones shown.
Note
Nameservers are specific to your order. Read them off the form rather than from anywhere else: two Premium DNS orders are not guaranteed to answer on the same hostnames, and a pair typed from memory is a domain that stops resolving.
What moves with it
Everything the domain serves. The website, the email, any verification records another service asked you to add — all of it is answered by whichever nameservers the domain is delegated to.
So before you press it, have a copy of your current records. Anything that exists in the old zone and not in the new one stops working the moment the change propagates.
See How DNS propagation works for why that is not instant, and What records a Premium DNS zone holds for what needs to be recreated.
Going back
Changing the nameservers back is an ordinary nameserver change — Change your domain's nameservers. The Premium DNS order itself stays; it cannot be cancelled from your account, and it keeps renewing until you tell us otherwise.