Think about it like learning to speak again. You practice several techniques constantly which help to prevent the main causes of stuttering in the three sections of the auditory system. You begin learning these techniques slow (40 to 60 syllables per minute) and slowly advance until you hit your control rate, whatever that might be where you can effectively utilize the techniques without stuttering. The two weeks intensive (typically it is three), 6 hours a day of practice, is designed such that you become very used to speaking that way before you leave the program. Although you'll still have to practice after leaving the program to retain fluency. It is the ISTAR program at the University of Alberta if you are interested.