How do you repair a side passenger mirror on a 2003 Honda Odyssey The glass fell out but did not break. The electrical part still works. I need to get the glass attached to the electrical unit?

If it is a heated glass unit then you should just be able to re-attach the wires coming from your mirror assembly to the terminals in the glass. Use silicone or urethane (automotive grade) to adhere it on the backing plate. If it is power only then just reattach with the silicone or urethane. If the terminals have come off off the mirror glass then you have to get a new piece of glass.