How is this unit attached to the cabinet?
Look real close at the trim. You should see four screws, holding the trim pieces to the cabinet (unless you have an over-the-range model). Removing the trim should allow you to slide the microwave out of the hole. If you have the OTR model, You’ll find two or three screws in the cabinet right ablve the MW. Removing them will allow the oven to be tilted down and removed from a bracket along the rear wall.