Its not quite that simple for a finish mower as there is an upward bend on the trailing edge of the blade to create vacuum or lift to suck the grass upward while cutting so you don't leave strips of longer grass where the tractor tires smashed the grass down. However, you may be able to find an equivalent blade for the opposite direction of rotation. I think that most finish mowers already have the opposite rotation direction (left discharge) as compared to belly mowers.