How do you uninstall an OTR microwave oven - GE Spacemaker 152K was installed in approximately 1992. We need to replace it. Thanks for any help!

It helps to know how they are installed. Remove the black plastic grill on the top by backing out two small screws. Once this is off you will see at least two screws that reach all the way to the back wall plate hung on the drywall and studs. remove them. There are one or two screws, more like small bolts, that come down from the cabinet above, remove the duct work and theses bolts but have a helper handy. Both of you should lift the back edge if the unit and you will find it was hung on a small lip across the top of the wall plate. If you are installing a new unit read their installation directions, they are all quite similar.