Pull the low pressure hose away from the inflator. You may hear a loud popping noise, this is just the sound of air escaping from the valve as you remove it from the inflator.
Now that the hose is disconnected your BCD will stop auto-inflating. You can adjust your buoyancy by releasing air from your BCD by using your deflator or a dump valve.
You can now manually inflate your BCD (as learned when performing the Fin Pivot)