Because I was unable to attend the interview Because at present I have already agreed to work with a company. Therefore must notify the company. Thank you to the company for giving me the opportunity to interview this time. And I apologize for not notifying you in advance as I should have.
I am unable to attend the interview because I have agreed to work for a company. Thank you for giving me the opportunity to interview. I'm sorry I didn't notify you in advance.
Because I can't attend the interview now, because I have agreed to work in a company, I must inform the company and thank the company for giving me an interview this time. I'm sorry I didn't inform me in advance.