Some exterior wood doors are made from panels fitted into a frame. These are called panel doors and come in both raised and flat-panel styles. Sometimes these panels become damaged or scratched and need to be replaced. Fortunately, you'll be able to remove and reinstall the panel without buying a new door. Whether it is flat or raised, panel installation is the same.
Remove the hinge screws from the top hinge and bottom hinge (in that order) with a screwdriver and remove the door from the frame. Place it on a table or work bench.
Remove any tacks, staples or nails holding the corner together with a hammer pry. Then use a mallet and the scrap wood to dislodge the corner. Place the scrap piece of wood against the frame board edge and tap it with the mallet like a chisel, to dislodge it from its joint. Once free, pull the frame piece off the door and put it aside for now.
Remove the door panel by sliding it out of the channel grooves in the door frame. Clean and sand the inside of the channel with a rag and 120-grit sandpaper.
Slide the new door panel into place. Apply wood glue or staples to the frame and panel to hold it in place, depending on what your original door frame and panel used to secure the panel.
Replace the bottom of the door frame and tack this back together with a nail gun.