How to Soften bread in microwave

In the oven: Preheat oven to 200 °. Wrap the bread in a damp (not soaking) paper or cloth, place it on a baking sheet and leave it in the oven for 5-10 minutes.

place the bread in a microwave

we let it be a couple of seconds. (With 5 or 10 already.)

remove and already, the bread softens, have to eat fast because after a while it endurese again.

Why is this?

Simple Any food has a moisture content, or water.
The bread, put it in the microwave, each time by the action of energy on the hydrogen bridge bonds, will make these vibrate and pass into the vapor state, the first time, the second time, there is less water to evaporate, and the third time even lower.
And a minor amount of water in a food, higher hardness.