You become capable, or proficient if you are already capable and are 5th level or higher, with the Persuasion skill.
Additionally, you can add half your Aptitude Bonus (min 1) to any Charisma check to calm violent emotions or to counsel peace that doesn’t already use your Aptitude Bonus. You must make this entreaty in good faith; it doesn’t apply if proficiency in the Deception skill applies to your check.