What is the difference between microwave and convection microwave combo? I have been using microwaves for a long time and just a few weeks ago, I saw a convection microwave combo in my office. I didn't know before that it existed.


I saw people putting aluminum foil in it, which I can't use in a normal microwave. How does that work?
I have also heard that we can not put any metal in microwave but the bottom rotating plate itself was made of metal. How does that work?
Regarding heating, I want to know if it still uses microwave technology or a different heating technique, because I have heard it does not use microwave heating. Will convection oven be better for reheating food?
Most of this has been asked and answered, just not all together in one place.  See:


What are the pros and cons of Convection Microwave Ovens?
Is it wise to use an aluminum foil in the microwave? Is there a substitute for the aluminum foil?
Why is some metal safe to use in a microwave, but others not?


The combination oven by its very nature has a two different cooking modes:  microwave, and conventional heating.  Some can do both at the same time, to speed cooking while mitigating the disadvantages (no browning or crisping) of microwave cookery.

The mode you choose to use when reheating food will determine  how it gets reheated.  Some foods are best done by microwave (such as soups, stews, braises, saucy curries), and some by conventional cooking (fried foods, some breads or toast).  This is not to say there is an ideal way to reheat everything:  some foods (like pizza or deep fried foods) are notoriously difficult to reheat well.