Switching between OS2 and OS2xl

Sorry if this is covered guys.
Am about to purchase XL, but still need to be able to switch back to OS2.
Can I do it by loading from the HD? or do I have to use a cf card?

Basically whats the deal between switching betwwen OS1, OS2 and OS2xl?
Cheers

you can switch easy between os1 and os2 OR osxl, but to switch back to os2 once osxl is installed, youll have to reinstall os2. bummer.

Thanks man,
so I have to reinstall OS2, then when I want to use XL I have to reinstall that?
Bummer but doable i guess