I had to do that to a selfish ba$tard of a neighbour who strung himself up from the stairs about 8 years ago!
We had had a falling out about 2 years previously and never spoke. One day his wife come hammering at the door screaming for me to help. Rushed into their house to find him hanging from the bannisters at the end of a very thick dog lead. I supported his body while his wife had to cut the lead with a bread knife. Got him on the floor, did CPR and kiss of life using a tea towel for protection but it was no use. When paramedics arrived I told them I think I've broken a couple of ribs, his response was, "thats the least of his problems, don't worry." At the inquest it was concluded it had not been a cry for help or a threat because he had known exactly where to place the rope for immediate result. The police had found a couple of books on hangmen and downloads on his computer about hanging so all my efforts were pointless.