Best advice for making a stutterer comfortable and minimize stutter?

Best advice for making a stutterer comfortable and minimize stutter? I work at a facility that assesses some professionals and their conversational skills with the general public. From time to time we get a person who stutters, and occasionally the person who stutters is given a little extra time for the exam (maybe ten minutes). Of course, this being a test, the person is naturally nervous and self-conscious, so I can imagine that it doesnt help things to cope with a stutter on top of all the other testing pressure. Are there things I can do quickly in our limited interaction/conversation to help them get through it, (eye contact, etc.,) to help them through it as smoothly as possible?