Bring the mower to a stop and turn off the engine.
Stand behind the mower handlebar and raise the entire cutter unit off of the ground by pulling up fully on the lever attached to the cross-bar located under the handlebar.
Push and hold the height adjustment handle located on the handler's side strut, forward against the bounce back pressure, to release the height adjustment pin to fall into the hole representing the desired lower cutting height.
Loosen your grip on the spring loaded adjustment handle slowly to fix the pin at the new lower cutting height.
Lower the cutting unit back to the ground by pressing out on the lever attached to the cross-bar located just under the handlebar.
Restart the engine and proceed with your mowing.