How to Degas Huma Regulator

I installed a Huma reg in my Impact MKI and wondering if there is a trick to degas after removing the bottle? With the AMP regulator a person could just dry fire once, or turn the reg screw CCW a little to degas, but the Huma reg doesn’t seem to work that way.

The only way I have been able to degas is by loosening the RP gauge, which is not desirable.