The closest I think I came to doing this was to migrate a running Debian system from being an i386 system to being an amd64-system, in-place: https://wiki.debi

The closest I think I came to doing this was to migrate a running Debian system from being an i386 system to being an amd64-system, in-place: https://wiki.debian.org/CrossGrading https://wiki.debian.org/CrossGrading The first step is to update the kernel from an i386 one, so that it could run both i386 and amd64 binaries, but then you essentially overwrite every package with the version from the new architecture, and hope like hell it doesn't mess up. At the time I had a pair of servers, a mail-host, and a web-host, and I managed to successfully upgrade both, although it was a little scary. At least I had console access if things did get horribly screwed up.