Stupid pad question

Changing the pads on the single piston caliper discs I have on the car. Stupid question time.. is there an easy way to do this? The piston appears to be out a bit so to put the new pads in I don't have quite enough room to slide everything over the rotor. Do I need to loosen off the bleeder valve so the piston slides in further in order to get everything working? This is frustrating..