An appraisal interview

As a new supervisor, you’re about to hold your first-ever appraisal interview with one of your subordinates, someone who has not been performing very well for the past 6 months. What should you keep in mind about managing the appraisal interview as you begin the conversation?
Have you performed an appraisal, or have you been the interviewee in an appraisal interview?
If you were the supervisor performing the interview, based on what you know now, what changes would you make? OR
If you were the employee being appraised, based on what you know now, what changes could your supervisor make to improve the process?