he's just putting a new filter in, so the tank can stay in place
You dont really NEED to de-pressurize the system. I changed about 30 fuel filters over the summer at a Ford dealer and never released the pressure. A little gas will spill out, but just cover your eyes and you'll be ok.
But if you insisit on doing it, just unplug the inertia switch that cyberstang was talking about, then start the car. After it uses the remaining fuel in the lines, the car will die. Change the filter, plug it back it, hit the button on it to reset it and start it back up.
hope this helps