Lean Change is an Adaptable Approach to change management versus Prosci which is a linear, step-by-step approach.
Lean Change sees resistance as valuable input versus Prosci which sees resistance as something that must be overcome by force.
Lean Change sees 'getting buy-in' as a continuous, ongoing co-creation activity versus Prosci which sees 'getting buy-in' as something that is done up-front.
Lean Change uses agile and lean startup to figure out what the right change is versus Prosci which limits 'agility' to the execution phase.
Lean Change advocates for the lightest-weight approach as possible versus Prosci which overwhelms change agents with standards and big processes.
Lean Change is based on real-world, in-the-trenches experience from agile coaches and change practitioners versus Prosci which is based solely on research, created by sales people.
Lean Change was created in a VUCA world as a response to in-adequate approaches to change versus Prosci which was created before the internet existed, and hasn't evolved with the increasing pace of change.