If it doesn't work - your body can't tolerate the band, you have serious complications, or you don't lose enough weight - you can have the band removed. You can also have additional , revisional surgery to a different weight loss surgery procedure.
1. Your insurance might pay for band removal due to serious complications, but probably not just because you changed your mind and wish you had chosen a different procedure in the first place.
2. I think I've said it before, but I'll say it again: NO weight loss surgery procedure of any description is going to work magic for you. So give it your best shot.