How can I upgrade/downgrade my service?
Process is as follows:
1) Order the new service
2) Request from support data migration from old to new
3) Request from support prorata from old service to the new service (optional, only if new value is higher than old one)
For data migration to happen usernames must match.
Data migration can take quite a bit of time, on small account you must reserve couple days for that to happen and to verify it. On super large accounts (say 50TB+) reserve week or more depending on your server load.
Prorata means moving remaining time from old service to new service