Are you cutting or welding?
You can't weld with propane. Acetylene provides a co2 shield as it burns. Propane does not.
As for cutting the flame is different and the heat in propane is in the secondary cone so you have to have the nozzle further away. I thing the nozzles are different too.
The hose change is a must as they'll get destroyed, the chemicals are different.
You need the two piece propane nozzles and to learn a slightly different lighting technique. New regulator I think is also meant to be used, I don't know why.