Lay a tarp on the floor next to the door opening.
Place two sawhorses on the tarp, evenly spaced out.
Close the door tightly. Remove the hinge pins, using a hammer and nail tap. Open the door to remove it from the space.
Place the door on the sawhorses. Remove the hinges and doorknob from the door, using a screwdriver.
Use a paintbrush and paint to change the color of the door. Wait 24 hours, and flip the door over to paint the other side.
Replace the old hinges and doorknob with a new style after you've painted the door. Attach the new hinges and doorknob with a screwdriver and the provided screws. Follow the manufacturer's instructions for installing the new doorknob.
Measure trim to add to the door. Use a tape measure to take measurements a few inches inside the door edges.
Cut the trim to the appropriate length, using a miter box and saw. Cut 45-degree angles, using the miter saw for the corners of the trim.
Attach the trim to the door, using wood glue. Allow the glue to dry for 24 hours.
Flip the door over and repeat Steps 7 through 9 to add trim to the other side of the door.