The driver's side mirror glass on the Hyundai Sonata is like most other automotive side-view mirrors. It is made of plastic with a reflective mirror coating on it. The reason Hyundai makes the mirror out of plastic is to improve the impact resistance of the mirror. However, it is not impossible for the mirror to crack upon impact with a passing vehicle. If the mirror does crack, you need to replace it before your next vehicle inspection. Otherwise, you risk failing the inspection due to the cracked mirror.
Slide the mirror to one side of the plastic housing it sits inside of. This turns the opposite side of the mirror outward so you can get your fingers behind it. If your Sonata has an electric control module or mirror adjuster, use that to adjust the mirror to one side.
Place your fingers behind the side of the mirror sticking out of the Sonata's mirror cover and pull the plastic mirror out of the cover. The mirror attaches with small metal clips. They are not damaged during the removal process.
Place the new mirror into the Sonata's mirror cover and press the clips into place by pushing on the centre of the plastic mirror. The clips bend around the mounting post or electric control module to hold the mirror into place.