If you're careful, and unclip the hose from the body, it might be possible to separate the two pieces even though the fitting on the hard line doesn't turn. Just be careful to hold both the fitting and the hose with wrenches, and then turn the whole hose. Make sure the hose is unclipped from its mount, because the mount holds the hex end of the hose from turning. I've done this when circumstances required (like, it's 9:30 on sunday night and I have to be somewhere tomorrow). The best solution of course is to replace the hard line, or to go ahead and break it and splice in a new piece with a double flare and a coupling, but it can be done.