How do Revolution and Reform differ from each other?

Revolution and reform have many different differences. For example, a revolution occurs due to the fact that there is a lot of discontent in society and people come from the bottom. The population itself rises and begins to make a coup in the country and strive for some kind of qualitative changes, but reform, these are changes in the country, often very serious, but they are from the top, namely at the initiative of the authorities. A revolution often leads to a change in the state system, as well as power, but a reform simply leads to changes, but power remains in its place.