Hold the nozzle upside down in one hand and with the other hand turn the shaft with the spring counter clockwise ¼ of a turn till is stops.Pull on the shaft and spring until it comes out.   For changing from the ¾ to ½ inch jet rotate the shaft 180 degrees and reinsert the shaft and turn clockwise to lock.   ALWAYS CHECK WHEN BACK TOGETHER TO SEE IF THE APPROPRIATE SIDE IS OPEN.
If you need change to a 3/8 or ¼ inch nozzle remove the shaft as instructed above Once the shaft is out, lift the body up and down while upside down until the cap comes out of the body. Push the existing jet inward from the outside of the cap and to remove the jet insert and replace with the desired new jet insert.  ALWAYS CHECK WHEN BACK TOGETHER TO SEE IF THE APPROPRIATE SIDE IS OPEN.
To clean the ratcheting mechanism, disassemble as above and flush all parts then reassemble the nozzle the same as above.