I had not too short pins, so I just cut the regulator out. Then with desoldering pump, I carefully removed the solder out of the holes, applying some heat. I finally was able to put the new regulator in and resolder it in place from the top, without removing the board. I was careful that the pins in the holes do not fall towards the socket and make some bad shorts.
BTW, I can send you some 431s. I received a handful. Just PM your address.