Apology Letter For Not Attending
Dear {Recipient},
I'm sorry I couldn't attend {event} {yesterday/the other day}. I had been looking forward to it ever since I received the invitation, but unfortunately, I wasn't able to go because of {reason}.
I'd also like to apologize for not {calling/texting} you, but I didn't want to bother you. I know how stressful it can be to {host/organize} a {type of event}. I heard it was a success though, so congratulations!
I hope to catch up with you soon. Do let me know when you're free.
Sincerely,
{Your Name}