1. Slave the 3200 as a master-backup to the 650 master (will require different IP address, etc as if you were staging that 3200 to exist concurrently with the 650 master).
2. Once you are sure the configs, master DB has synced, and that everything is working as you expected...
3. Once you are sure, take the 650 offline, let the 3200 come up as master, then re-IP the 3200 to have the old IP addresses of the 650.
As long as you can take an outage, which will be require anyway, that is the easiest way which minimizes risk of manual entry error.