Silly question about replacing the accumulator.

I have noticed fuel has started to leak out of the accumulator screw and it's going to need replacing. Typically I filled the car up the other day and it probably has nearly a full tank of fuel. Will I have to drain the tank or will the fuel pump stop it from pouring out when I remove the pipes?
Thanks.

I would plan for the whole tank trying to drain, how does the L pipe on the fuel tank to pump look? if its nice you coudl pinch it with pliers, or remove it from the pump side and use a bolt to block the end

Thanks John, the rubber hose to the pump was new last year so it should pinch, I'll try it out (I never even thought of that!).
Why couldn't I have noticed when it only had a couple of gallons left in it?