To remove the other side of the sliding glass door just do the same.
How to remove glass on pella sliding door.
Then tilt it out and you have it.
You should be able to remove the door by sliding it half way out then physically lifting up on the door itself.
Remove the threshold placed in front of the fixed sliding glass door panel.
The head stop is the piece.
Locate the screw cover on the vent panel s edge.
Locate the screws securing the pella sliding door s head stop in place.
You will see that it raises up just above the bottom of the sill.
Slide the vent panel down the tracks near the center of the door opening.
Use a flat head screwdriver to remove the threshold from the floor.
Place the screwdriver beneath the threshold edge flat against the floor and pry the wood gently up taking care not to gouge the floor s surface.