Cannot attend interview mail

Here is an example email that you can use as a template:

Subject: Regrettable Decline of Interview Invitation

Dear [Interviewer's Name],

I am writing to express my regret and apologize for not being able to attend the interview scheduled for [Interview Date and Time] at [Location]. Unfortunately, [briefly mention the reason for not being able to attend, e.g. "unforeseen personal circumstances" or "family emergency"].

I was truly excited about the opportunity to discuss the [Position] role at [Company Name] and appreciate the time you took to consider my application. Please know that my decision to decline the interview is in no way a reflection on the company or the position, but rather an unavoidable circumstance.

If there is any possibility of rescheduling the interview for a later date, I would be more than happy to discuss this further. Alternatively, I would be grateful if you could keep my application on file for future consideration.

Thank you again for your understanding, and I wish the company all the best in finding the right candidate for the position.

Best regards,

[Your Name]

Remember to customize the email to fit your specific situation and tone. It's also a good idea to proofread your email for grammar and spelling errors before sending it.