Sometimes you have to rehome them, I had an Amazon that for whatever reason would never take to me after a couple years, wasn't nippy or anything, or even a screamer except for mornings, but just wanted nthing to do with me, so I put her up for adoption knowing I was going to screen the people very heavily, and just keep her if I didn't find anyone suitable. Luckily I found a family that ran a parrot type rescue that were looking for the exact type she was. The thought even crossed my mind with my current Macaw due to his screaming and I almost found him a home as well. In the end the people that were interested in him were too old, and I hated the idea of of him bouncing from home to home for the rest of his life.