Sure, it is easy:
A few days prior to the transfer, in the DNS Zone file, set the TTL to be very very low.
Buy a new server, install it at the new place. Configure it like the first server.
Update the DNS Zone file to point at the new server, reinstate the longer TTL.
Remove the old server.
Et Voila! Near-Instant changeover.
This doesn't work when you are physically moving the server from one place to another, which appears to be what Amiga Inc are doing.
