An agent of change is someone who works to bring about positive transformation in a given situation. A CATALYST is an individual or event that triggers a process of change, while a DYE is a substance used to color something. A REVISER is someone who reviews and makes changes to a document, while an alterer is someone who modifies something. Finally, a mutagen is a substance that causes genetic mutation. All of these terms can be used to describe an agent of change.