Move a website to a new IP address

Export the current zone. Record the authoritative nameservers, the existing A and AAAA values and their TTL. Keep the old host serving the site.
Test the new origin with the real hostname and certificate. Lower the web records’ TTL one original TTL interval before the move. Preserve MX, TXT and unrelated records.
Change the web address records. Query the authoritative servers and two independent resolvers, then test HTTPS and a real application action. Check both IPv4 and IPv6 when present.
If validation fails, restore the recorded address values. Keep both servers available while caches expire. Restore the normal TTL after traffic settles.