If you need to stop fuel flow for safety or repair reasons, you'll need to disconnect the fuel pump's electrical connector or, in some cases, the fuel pump relay in the fuse box. This should only be done by someone with automotive experience and the proper safety precautions in place. Disconnecting the fuel pump relay is generally safer than directly manipulating the fuel pump wiring itself.
Caution: Working with fuel systems involves potential fire hazards. Be extremely cautious and ensure the vehicle is turned off and the ignition is switched off before attempting any work. If you're not comfortable performing this task, consult a qualified mechanic.