How do you generate a new "cattle registration secret key"?

Is it possible to generate a new CATTLE_REGISTRATION_SECRET_KEY for a Rancher Environment? If so, how could I do this?

Also, is it recommended to periodically cycle the secret key, or only if (potentially) compromised? If it is possible to generate a new secret key, are there any additional steps to take after doing so? (i.e. update the associated rancher agents?)