1999 Oldsmobile Cutlass changing fuel filter

I guess you mean de-pressurize? I use a pressure gage, aim the bleedoff hose into a container, hit the pressure bleedoff button. The pressure gage fits to the schrader valve. If you have an easy way to disconnect the pump, then just start the vehicle, let it run till it dies. Usually after the vehicle sits overnight with out the key being cycled or engine running, there isn't much pressure,but, you still need to be aware.