Answer
Changing the voltage for the 45HW requires replacement of the solenoid.
Part numbers for the solenoids are:
719251800 - B44613 40HW 12V SQUARE SOLENOID
719250640 - B44610 40HW 24V SQUARE SOLENOID
Applies To
45HW
Additional Information
Please Note: This requires taking the mortise case apart and should only be attempted by a trained professional.