When migrating your edge servers, one of the main fear is that we lose the traffic being served by the locations we're currently advertising on.
In order to migrate the edge servers and also retain the subscription on the locations, the following must be done to ensure that the traffic flowing to that location is never stopped.
1) Create the new edge under the same locations as the ones you previously have,
2) Wait for it to be approved in the market place,
3) Once it's been accepted, you could proceed with deleting the old edges.