You might be able to get it off with the use of a large channellock pliers or a plumbing pipe wrench. that body screws off counter-clockwise. If you don't have either of those tools or if you can't get it off with them almost any garage will either let you put it in a vice and break the body loose or they'll do it for you either free or for a couple of bucks. That is if you don't a have a decent size vice mounted on a sturdy bench.

Cheers