How to change voltage on LAMM M1.2, from 110to 220

I sent this unit to my friend in Europe and he is unable to change voltage to 220V. Please help, much appreciate any input!
In my Lamm preamps, changing voltage was a simple matter of unplugging the preamp, then opening the case and removing the fuse located in the 110v fuse holder, and installing a new fuse (of a different value specified near the fuse holder) in the 220v fuse location.

I don't know if the Lamm amps work the same way, but it would make sense that they would do so.
They don't.