The Sensible 12: No. 10

10. A change management plan must be in place in preparation for the inevitability of change.
Change is nothing to be afraid of; in fact if it wasn’t for change, there wouldn’t be a need for project management. The key is to have a change management plan in place which describes how a request is submitted to the project and how you will manage that change request. If this plan is documented and understood by all shareholders, change will be managed without disrupting the project.

I don't know what 'in place' adds to the content here. Yes, you must have a change management plan and the sponsor must participate in the development of the plan. He/she must also promptly give (or not) the authorisation of any changes (along with any investment and schedule changes) in cognizance of the benefit/value they will provide to the project.
The plan should include change proposal evaluation criteria to prevent the inclusion in the project of whims that do not go to the mission, but absorb time and resources nonetheless, depleting the project out turn value.