Dear Mr. Clark,
I would like to express my apologies for not being able to keep our 9 oclock appointment. I had a small accident on my way to school. I will come over to your apartment the day after tomorrow ― Monday, November 2, at 9 a.m. if that is convenient for you. I will check my mailbox tomorrow to see if you have left a note for me. Otherwise, I will see you at nine, Monday morning. With many apologies.
Li Xiaomei