I long ago gave up on the customer service desk in the Flounge. (I assume we're talking about that window across from the toilets.) They have never been able to handle anything as simple as a seating change for me, let alone a rebooking.
The agents at the entrance to the lounge have offered to arrange mobility assistance in the past. (Back when I was traveling with a broken ankle but didn't know it. I foolishly declined the offer.)