How do you politely cancel a appointment?
How do you cancel an interview that you don't want?
Call or Email the Hiring Manager
Should you decide that there's no way you'd want the job (or if you've decided to accept another job offer), call or email the person who scheduled the interview to let them know that you are not going to attend the interview. Provide as much notice as possible.
How do I decline an interview offer?
Dear Name: I'm grateful for the opportunity to interview at Company Name for Job Title. Since I initially put in my application for this position, I was offered—and accepted—a job at another company, so I'm respectfully declining this offer. I wish you all the best in your search for a candidate.