To look professional when rescheduling or canceling an interview when you are no longer interested, you need to do it well in advance. It is crucial as it gives your employers an understanding that you care about their time and appreciate the opportunity to become part of their team. You can send an email explaining the situation and honestly stating the reason why you cannot attend a meeting. If your plans have changed or if you already have a job offer from another company, write about it calmly and respectfully. Express the hope that you will have a chance to work with them some other time in the future.