Distribution block reset??

Ok I think I know what I did wrong now I need to know how to fix it. I installed a completely new brake system on my 72 Scamp KH power disks up front drums rear. When I tried to bleed the rear brake lines I pushed the pedal to hard and trip the switch in the new distribution block. I now can get fluid to the fronts but can't get fluid to the rears. How do I recenter the valve?