What to say when you forgot an appointment?

You should write a letter or email and begin with an honesty apology and use phrases like “I apologize for missing the meeting” or “I express regret over not being able to attend.” Do not make excuses or give an insincere explanation and ensure you communicate that you genuinely feel sorry.

How do you apologize for missing an appointment?

Please accept my sincere apology for missing the pre-scheduled appointment with you today at ___ a.m. / p.m. I am not going to make any excuses now. It was my fault. I regret missing the same. I would appreciate it if the appointment can be postponed to a later date.