I don't know the 50SX specifically but if you're not going to remove the ring from the piston then there's no problem. Just clean everything and put it back together. If the ring is pinned then make sure the gap is aligned with the pin before you try to reinstall the piston in the liner. If you've got varnish then one thing to check is that the small end of the rod is free to move on the gudgeon/wrist pin.

If you're going to remove the ring then do it a spiral. Lift one end free with your fingernail until it can just lay on the piston crown then slowly work the ring around and out of the groove so that the free end gradually moves across the crown. Refit in the same way. If the ring is pinned then check to see if the pin is centred in the groove (the ring can go on either way). If the pin isn't centred then it'll have a matching end gap so it can only go on one way. If the ring isn't pinned then they rotate slowly as the engine is running so it can be refitted any way you like.

I've found that a cleaned and reassembled ringed engine needs a couple of tanks of fuel before it regains it's seal and then it's as good as new.