Michell HR PSU converting from 220 to 110

I have a chance to purchase a used HR.
I was told to convert the unit from 220v to 110v was to change the fuse. Doesn't sound right to me. Does anyone know the procedure. The US distributor for Michell doesn't.
Thanks Mike
Disconnect the brown wire lead from the switch and pull out a white one from underneath the transformer.Also swap the fuse for double the value.