First detach the arm that raises the window, there is a snap ring on the inside. Then remove the small metal tab that limits the window movement forward and back, this is removed by pulling straight down with a set of needle nose pliers, be careful with the tab. Next lift what you have in place for a window or just the hinge a work past where you removed the tab. Sometimes there is not enough clearance to remove window, most will not agree, but I pry hinge attached to trailer open a little to create clearance. Slide window out.
David & Diana