Legacy pre-paid vs hourly

There wouldn't be a way to have both a legacy and metered server on the same account, you'll need a second account if you wanted to keep them separate.

If you do want to go down this route, just shoot support a ticket stating that you'd like to move the Linode. On the second account that will receive the Linode (https://manager.linode.com/support/ticket/new), open a ticket referencing the first account's ticket #, then state you'd like to accept that Linode. Should go without an issue.