As a PMO what is the best approach to "Change Management" and "Transformation Initiatives"?

Make sure that

• Change management policy, procedures, and standards are integrated with and communicated to IT and business management functions

• Roles and responsibilities affecting change management are defined, designated to qualified personnel, communicated to the organization, and enforced throughout the change management process.

• post change review processes provide continuous benefits to staff and business operations alike.

 

The best approach is to initially identify the pain areas which are currently being experienced by the business departments/sections etc.
try to concentrate on resolving those issues by proposing a practical solution.
Always try to"simplicity".
DO NOT complicate things.
Further, first get the basics right and develop very simple templates train and coach people on the use of the templates by elaborating the value of their use so people can feel the value of using system rather then treating as a liability.
Then after some time when they reach at maturity level, put more advance information in the templates and build a standard system or process.
Keep the maturity of the people in mind rather then concentrating on the maturity of PMO itself as Both have equal significance and should excel in parallel as excellence is any one of them will not help you in achieving your objectives.