To remove the sliding pane, open it all the way, then shift it upwards and rotate the bottom towards you. Remove any screws that may be holding it in place. Most of the time the center vertical meeting rail and fixed panel come out easily after removing the screws. You may need to pry it out with a mallet and screw driver. If that does not work you can use a hacksaw to cut through the meeting rail. You should not need to break the glass. The aluminum outer frame can remain in place.