Just loosen the lock nut and turn the rod.
I actually never even loosened the lock nut when I did mine. Damn thing was on too tight and those are tight quarters down there. I just grabbed the rod with a pair of pliers and turned it. It still would turn, it just threaded through the lock nut which was on so tight it never moved.
The easiest way to turn would be to remove the cotter pin attaching it to the pedal and then turning it, but I just stopped on the side of the road and adjusted mine in a parking lot real quick because it was irritating me :lol: