Ready an action...

Ready an action
When you ready an action, you prepare to react to a creature’s action or an event. Readying an action is a way of saying, “As soon as x happens, I’ll do y.” For instance, you could say, “As soon as the troll walks out from behind the corner, I’ll use my pinning strike and interrupt its movement” or something like, “If the goblin attacks, I’ll react with a crushing blow.”

READY AN ACTION: STANDARD ACTION

Choose Action to Ready: Choose the specific action you are readying (what attack you plan to use, for example) as well as your intended target. You can ready a standard action, a move action, or a minor action. Whichever action you choose, the act of readying it is a standard action.

Choose Trigger: Choose the action that will trigger your readied action. When that action occurs, you can use your readied action. If the trigger doesn’t occur or you choose to ignore it, you can’t use your readied action, and you take your next turn as normal.

Immediate Reaction: A readied action is an immediate reaction. It takes place after your enemy completes the action that triggers it.

Interrupting an Enemy: If you want to use a readied action to attack before an enemy attacks, you should ready your action in response to the enemy’s movement. That way your attack will be triggered by a portion of the enemy’s move, and you will interrupt it and attack first. If you ready an action to be triggered by an enemy attack, your readied action will occur as a reaction to that attack, so you’ll attack after the enemy.

Note that an enemy might use a power that lets it move and then attack. If you readied an action to attack in response to that enemy’s movement, your readied action interrupts the movement, and you can attack before the enemy does.

Reset Initiative: After you resolve your readied action, move your place in the initiative order to directly before the creature or the event that triggered your readied action.