Currently the switch to a standby CM requires manual intervention.
The benefit of the Central Manager is that it provides configuration management, device management (software upgrades, etc.), reporting, and security services from a single, central location. Note that the security services, such as disk encryption keys, SSL certificates, etc., are available from the Standby CM (in the event that the Primary CM is unavailable) without the need to promote the Standby to Primary.
Regards,
Zach