change is a process

Change is a process matching the speed that employees navigate the change process to the speed of the business change... 

Effective change progresses along the two axes (phases of business change and phases of employee change) at the same time. We must manage the implementation of the technical solution and the people side of the change concurrently. If we fail to manage these two components together, then we can experience the failure points shown above.

Jeffrey M. Hiatt & Timothy J. Creasey

Change Management: The People Side of Change, by Jeffrey M. Hiatt & Timothy J. Creasey Prosci Inc. 2012. P.37-39

a solution that is technically "right"

Just having a solution that is technically "right" does not guarantee that employees will make the necessary changes to their behaviors and work processes. Employee commitment, buy-in, and adoption do not stem from the rightness of the solution, but rather from the employees moving through their own change process. It takes more than the right solution to move employees out of the current state that they know and into the future state they do not know (and sometimes fear).

Jeffrey M. Hiatt & Timothy J. Creasey

Change Management: The People Side of Change, by Jeffrey M. Hiatt & Timothy J. Creasey Prosci Inc. 2012. P.31

from "how high?" to "why?"

The evolution from the traditional values of control, predictability and consistency - values that made change relatively simple to implement - to the new values focused on accountability, ownership and empowerment has made the implementation of top-down business change more difficult. 

...These... employees now question and resist new change initiatives. The response of the employee has shifted from "yes, sir" to "why are we doing that?" If your employees have embraced some or all of these new values, change management is not an option for successful change, it is a requirement. 

Jeffrey M. Hiatt & Timothy J. Creasey

Change Management: The People Side of Change, by Jeffrey M. Hiatt & Timothy J. Creasey Prosci Inc. 2012. P.26,27

lacking sponsorship

While the criteria and roles for a sponsor may seem straightforward, many projects today struggle because they lack sponsorship for their change. In some cases executive sponsors authorize the change (sign the check) and kick off the project, and then disappear. They abdicate the role of sponsorship to a mid-level manager or consultant. 

Jeffrey M. Hiatt & Timothy J. Creasey

Change Management: The People Side of Change, by Jeffrey M. Hiatt & Timothy J. Creasey Prosci Inc. 2012. P.24

apply change management early

We must, at some point, ask the question: How much resistance might we avoid if we would apply change management early and effectively? In the example with the ERP implementation case study, rather than simply designing a "great" solution to the manufacturing and inventory structure and beginning implementation, a proactive change management program could have been put in place to engage and support employees through the transition. Rather than waiting for resistance to happen, or being taken by surprise when key employees resisted the change, the leadership and project team could have assumed that resistance to change is normal and natural. If they had started with this as a basic presumption of change, then their actions and planning could have prevented the project failure and unfortunate consequence to the customer.

Jeffrey M. Hiatt & Timothy J. Creasey

Change Management: The People Side of Change, by Jeffrey M. Hiatt & Timothy J. Creasey Prosci Inc. 2012. P.22