In recent years, many car manufacturer's have switched to using plastic or composite body panels to reduce some weight and make bodywork less of a hassle. To remove a dent or crack, you now simply replace the body panel in question with a new one. Removing the body panels is actually fairly simple, and can be performed by any do-it-yourself mechanic.
Crawl under the side of the car where the body panel you want to remove is located. Find the screws holding the trim in place on the lower portion of the car.
Use a screwdriver to remove the screws, then slide the trim off of the bottom portion of the car. This exposes the mounting screws for the body panel.
Use a crescent wrench to remove the body panel mounting screws. Repeat this process on the other sides of the body panel and then carefully slide the body panel out of the way.
