Hi, Dali,
Sorry that I was not able to go to your birthday yesterday, as one of the friends came to see me at the same time..
Yours
Best,
***
Hi Dali,
I am sorry for not attending your birthday party yesterday. I was not able to come because a friend came to visit. Please accept my apologies.
Yours,
XXX
Zhang Dali,my work compaion ,He held a birthday party yesterday.I was visiting a friend and could not been invited to attend to that I worte to him an apology
Your colleague Zhang Dali held a birthday party yesterday. However, because of your friend's visiting you can not attend his party. Thereby, you write a letter to apologize to him.
Your colleague Mr Birthday party held yesterday, because you have friends visit, it can't invited to attend this letter to you, he apologized