Charisma has two separate systems, depending on whether the user has a Charm trait or not. Both systems make use of a resource called Leverage.
A character starts with 1 Leverage, with +1 per 50 CHA, to be used throughout a thread. Leverage can be used to take a Charisma action, or to block one.
The basic Charisma actions can be used by any character. Charm actions are for characters with a Charm trait or a naturally seductive species, and are built around the Trance debuff.
Skills Guide