Dear (Recipient’s Name)
Today is my son’s birthday, and we are celebrating it in the evening. So I need a half-day leave after lunch so that I can take care of my son’s birthday works. I have sent you all emails regarding the ongoing new project. I will be available on my phone (phone number) and email id (email address) in case of any emergency. Moreover, I have guided (colleague name) in case any query arises. I am sure the team will handle the work nicely in my absence. I hope you understand my situation.
Yours Sincerely,
(Your Name)
