I know on my other coach (was a Georgetown) you pushed "in" at the pivot point, then rotated. I forget if the arm was straight up or down, but think straight up -- push, then rotate and it should come free.
Hard to describe since I don't really remember, but give the push a try.
Higher end Flexsteel or other seats may be different.
2003 Newmar Dutch Star 4006 (Spartan)