I don't have a 120/220 TLR Rollie, but I suspect that all you need to do is set the switch to 220 and make a change on the film pressure plate and you are ready to go. Be aware that 220 film has a tendency to light pipe and you may very well have a couple of spoiled images. I no longer use 220 film because of this although I have 4 MF's that use 220 as well as 120.