Reformation, reform can both denote a making better or a giving of a new and improved form or character and are sometimes interchangeable without loss.
Reformation is the more usual term as a designation of a movement that has brought about many revolutionary amendments or improvements, especially in morals or religious practices.
It is also appropriate when the idea of making over so as to eradicate defects is stressed.
Reform , on the other hand, is more usual as a designation of an attempt to remove abuses, correct corrupt practices, or to make changes for the better.
Reform also applies, as reformation does not, to a particular or specific amendment, whether achieved or proposed, as a measure of reform.