Hint: Script out your conversation in advance … a practical guide
This is a great technique to use when discussing any tough (or emotionally charged) issue. The technique is called “DESCRPT” and it is quite literally a conversation you can script out in advance to keep you focused and on track. I first learned this technique while at Apple … in a management training class … and have adapted it and used it ever since.

D: Describe
The behavior that is problematic. Remember to criticize the behavior not the person. Be as specific as possible.

E: Emote
Tell the person how you feel. Disappointed, angry, ashamed, embarrassed. Say it, but keep it short and to the point. By definition your feelings are valid even if the person you are talking with will not ‘fess up to your view of the behavior in question.

S: Suggest an alternative
How would like this type of thing handled in the future? Provide the person with a positive model for their use “next time”.

C: Commit
Get the person to commit to the behavior change you are requesting. That way, they “own” the performance problem and take responsibility for correcting it.

R: Ramifications
If this is the second or third time you’ve had to discuss this same issue with the person, it’s time to start talking about ramifications. For example, “as we’ve discussed, these problems are so serious that one more incident will mean I’ll have to pull you off the project for good.”

P: Pull back.
Cut your conversation short. Don’t make small talk or otherwise try to dress up the performance conversation as something it isn’t. Your goal should be to get the person out of your office so they can compose themselves and reflect upon what just happened.

T: Time.
Set a date on your personal calendar when you’ll revisit the issue. That way, you can make sure the problem gets solved one way (behavior change) or the other (taking further action … those pesky ramifications discussed earlier.)