Ready an Action

The ready action lets you prepare to take an action later, after your turn is over but before your next one has begun.

To "ready" requires a standard action, but you may ready
a standard action, a move action, a swift action, or a free action.

To do so, specify the action you will take and the conditions under which you will take it.

Then, anytime before your next action (turn), you may take the readied action in response to that condition.