There isn't a specific CF, but if you've set the camera to focus with the * you can get the same effect by letting go of the * when you've got the desired focus. Alternatively, you can register Custom settings with AI Servo and One Shot focus selected (though you'll need to make sure the rest of your settings in the two Custom modes agree).
BTW jdizzle. jr_senator is 100% correct. RTFM, however phrased, is a completely unacceptable answer. See also the rules, in particular 4.9
If you know an answer to a question either answer it or say nothing. Giving newbies blunt answers like "search the forum" is not allowed - please use the typing effort to giving the answer instead. Or just give the link to that post you wished the newbie should have searched for. Respect newbies - you were a newbie once.