you don't mention a mast height or number, but as a general rule they either have a nut, bolt or some sort of snap ring holding the end of the cylinder's ram to the mast channel.
lift the mast into the second stage and chain it up with a properly strong chain, remove whatever attaches the cylinder ram to the mast at the top, and lower the cylinder (hopefully just using the lower function, if not you might have to put a little weight on the cylinder ram). I use a chain wrench on the gland nuts. I have had some where we had to take the cylinder out of the machine to get the gland nut loose, but far more can be unscrewed without removing anything of the cylinder barrel (jug).