Dont really have to.What you do is remove the piston pin and reverse the crankshaft and leave the piston in the same position.Then put the piston pin back in.Dont even have to remove piston from cylinder,just drop down low enough to remove wrist pin.Dont have to expose rings at all.
Also,most engines the ports are at 12 oclock and 6 oclock running with the crankshaft.Most pinned rings are done at 5 and 7,or 11and 1 so they ride on each side of the ports where the cylinder is smooth all the way to the dome.If they dont,thats when youll see the post in the exhaust port so the ring doesnt hang on the edge.