Insert a flathead screwdriver into the right side and pry it out. The vent rotates on two little plastic things. I think the left one is round and the other has one side round and the other squared off. This one is much easier to get out.
Hope this helps.
P.S. It may help to unscrew part of the dash to allow for stress.
Hope this helps.
P.S. It may help to unscrew part of the dash to allow for stress.