Technology Enabled Organizational Change Strategy

Change is a permanent organizational challenge and it does not matter what industry, size of enterprise or organizational structure. Complex collaboration models, the shorter product lifecycles, the variety of products that require attention, the increased product complexity, the advancing information technology and lastly the economic situation. These are some examples of the reasons and accelerators of change.
What is the ability of organizations to execute change, what are the drivers, what are the impediments behind the need, how well do companies execute operational initiatives. Specifically this last topic is the reason to work with experienced consultants. What are the enablers of success?