Reformation

Overview
Reformation allows you to reform into any country as long as you reach the following requirements: Once you reach the above requirements, you can reform using the Decision page inside the Government Tab.
 * 50 Political Powers.
 * Own all of the target country's starting provinces.
 * The target country has more Max Province than your current country.
 * The country that you're reforming into currently does not exist.

Reformation gives you the following benefits:
 * All of the target country's starting provinces become your core provinces.
 * Your current country will become the target country.
 * Your country's max province will increase to the target country's max province.
 * Allows you to use the target country's Political System.
 * Stops all current revolution(s).

Trivia

 * Reforming into The Roman Empire was possible and can be easily done before the overextension revolt risk per province became unbearable.
 * Reformation is rarely performed due to its difficulty.