Peacemaking
Note: Peacemaking skill has two different modes, Area Peacemaking and Targeted Peacemaking.
Area Peacemaking:
Activate the skill via macro or skill button and target yourself. If successful, all aggression in the area will cease for a few moments. Players will have to re-attack their targets.
Targeted Peacemaking:
Activate the skill via macro or skill button and target a creature. If successful, the targeted creature will either remain non-aggressive or stop attacking it's target until a sufficient attack upon it breaks the trance or the bard loses line of sight for more than 10 seconds.
Training:
Obtain a few dozen musical instruments, either from a carpenter or NPC. Use the Peacemaking skill and target yourself(Area Peacemaking). Repeat until the desired level is achieved.