Kohler sink stoppers use an assembly of several parts, to control the movement of the stopper in the sink's drain. The lift rod, or the bar that comes out of the hole in the faucet, attaches to a piece called the clevis strap on the underside of the sink. The clevis strap has several holes in it, which you insert a rod piece through and secure the rod in place with a butterfly clip. The other end of the rod goes into the drainpipe, where it pushes the stopper up or lets it drop down in the drain.
Push down on the lift rod, or the piece on the top of the faucet that controls the stopper's position in the drain, lifting the stopper up. Pull the stopper up and out of the drain assembly and place it aside.
Turn the nut that attaches the sink's stopper assembly to the drainpipe counterclockwise, removing the nut. Pull on the rod that sits inside the drainpipe, removing it from the pipe.
Pinch the butterfly clip that sits on the other end of the rod that was inside the drainpipe, and then slide the rod out of the hole in the end of the clevis strap. Turn the screw at the "C" shaped portion of the clevis strap counterclockwise with your hand enough that you can slide the clevis strap off the end of the lift rod.
Pull up on the top of the lift rod to remove it from the sink's faucet. Reinstall the sink's stopper assembly by reversing the steps you followed for the removal.