how to remove stock cats

[gatesy21]

Guys I need a little help, I tried searching but could not find what I was looking for. I am replacing the stock exhaust and cats with corsa and RT cats. I have the stock exhaust and crossover off. I am trying to get to the clamp on the cats but must be missing something. That thing is a challenge to get at. Is there any easy way to remove the stock cats? Any help would be great!