Final answer:
In order to cancel an extension with a significant benefit or an approved Physical Fitness Assessment Separation Waiver, the CO requires authority from a higher-ranking officer.
Step-by-step explanation:
In order to cancel an extension that gained a significant benefit or has an approved Physical Fitness Assessment Separation Waiver, the CO (Commanding Officer) requires authority from the respective higher authority. The CO does not have the power to cancel such extensions on their own. They need to seek permission or authority from a higher-ranking officer or a superior in the chain of command.