Change agent

A change agent, or agent of change, is someone who intentionally or indirectly causes or accelerates social, cultural, or behavioral change. Because of their importance, change agents are the object of scientific research. Captology, developed at the Stanford Persuasive Technology Lab, for instance, systematically studies how interactive computing products can be used to influence the mind.
See more at Wikipedia.org...

groups or individuals who use their skills and relationships to lead and implement change in an organization.

An individual from within or outside an organization who facilitates change within the organization. May or may not be the initiator of the change effort.