Open the lock box lid employing the current code. Once inside the box, remove the front panel by pushing down on the lever directly above the code dials.
Locate the reset button. This is on the outside of the rear portion of the lock box lid. Slide the reset button to the left. This clears the current code so that you may enter a new one.
Input your replacement code one numeral at a time. Once the new code is set, slide the lock box reset button to the right. This locks your new code in place.
Test the new combination before replacing the front panel. After replacing your keys in the lock box, mix up the code numbers to disguise your new code.