Lift the toilet lid straight up, and carefully set it aside. Removing the lid reveals the toilet lever trip arm inside the tank.
Disconnect the flush chain from the trip arm. A hook at the end of the chain threads into an eyelet in the trip arm.
Locate the mounting nut that joins the trip arm and lever to the side of the tank.
Rotate the mounting nut clockwise with an adjustable wrench. The mounting nut's reverse threads require a clockwise turn to loosen.
Slip the loosened mounting nut down the end of the trip arm.
Pull the Kohler lever away from the toilet. Continue to pull until the trip arm comes away with the lever.