the link below will take you to the installation instructions if needed.
It is much easier for two people to remove the microhood. If attempting alone, please move the range out so you can get under the micro to support the weight. If the range stays in place, protect the top from damage.
1. make a landing site to the side to protect the floor when putting the micro down after removal.
2. Disconnect the power cord in the cabinet above.
3. loosen the two screws in the bottom front corners of the cabinet above. When removed the front of the micro will drop, be ready for the weight. Busy times, tools in hands microwave coming down in front.
4. tilt the front down. pull the cord out of the upper cabinet.
5. with micro still tilted down in front, lift the back of the unit upward to free it from the wall plate.
6. remove the fasteners in the wall plate and remove.
Congrats, begin celebration.
http://www.managemyhome.com/mmh/lis_pdf/OWNM/L0211226.pdf