Can you stop yourself? (E.g. a friend comes around a corner instead of an enemy but your Readied action was to go off when someone rounded the corner)
Can you stop yourself? (E.g. a friend comes around a corner instead of an enemy but your Readied action was to go off when someone rounded the corner)
yes, you may stop yourself from executing your action.
Readying an Action
You can 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, you may take the readied action in response to that condition. The action occurs just before the action that triggers it. If the triggered action is part of another character's activities, you interrupt the other character.
Although, in the story context and the extremely broad way you set up your readied action's condition the GM might want you to do it anyway.
Can you stop yourself? (E.g. a friend comes around a corner instead of an enemy but your Readied action was to go off when someone rounded the corner)
Yes.
...Then, anytime before your next action, you may take the readied action in response to that condition...
EDIT: You ninja!
Can you stop yourself? (E.g. a friend comes around a corner instead of an enemy but your Readied action was to go off when someone rounded the corner)
No you don't have to take the action. As an example if you are waiting around the corner with a baseball bat, and someone comes running by that is not the intended target you don't have to take the swing, but I do understand some GM's might make you do it at certain times which is why I would advise you to word the readied action carefully.