I have decided to accept a tenure-track assistant professor offer. But at this moment, I still have a virtual on-campus interview with a different university. It is now the time to inform the university that I won't be able to participate in the interview. Three days ago when I was still waiting for a pending offer, I told them that I would attend the interview. I want to seek some suggestions about turning down the interview invite in a professional manner.
Dear [name of person you were communicating with],
I have an update about my job search. Since we last talked I‘ve received a tenure track job offer from another institution, and have accepted it. Consequently, I am withdrawing my application at your department, and am cancelling my upcoming interview with you and your colleagues.
I do very much appreciate that you considered me for the position, and hope that we will have occasion to meet in the future.
P.S. Congrats on the job!!!