1991 Dodge Caravan Ignition Lock Cylinder

I had an ignition lock cylinder wear out and all it done was turn completely around. I bought a new one and put it in, and now it is stuck and I cannot remove the new cylinder, how can I get it to come out? I made sure the lock pin was down and it still won't give, any answers on how to get the new cylinder back out? Thank you in advance. The reason I need to get it back out, is because the new cylinder is defective, key will not turn at all.