I just boarded UA676 IAH-DCA. I'm sitting in F on a paid TOD upgrade of an econ ticket. During preboard, a lady got on in a fully imbodilizing leg brace, and is seated in an E- aisle seat. As soon as I boarded, I told the FA at the door I wanted to give her my F seat and move back. The FA said "you can't do that. If you give up your seat, it will go to the next GS on the list, which is fair." As I was blocking the aisle and not wanting to cause a scene, I said nothing and sat down. I'm sitting here stewing, as boarding is ongoing.

NOT flyer friendly. Do I do anything further?