I will be out of the office starting (Starting Date) through (End Date) returning(Date of Return). If you need immediate assistance during my absence, please contact (Contacts Name) at (Contacts Email Address). Otherwise I will respond to your emails as soon as possible upon my return. Thank you for your message. How do you respond to holiday greetings? "And (also) to you!" You too! Thanks, same to you! Happy New Year to you and yours (when you want to extend the wishes to the other person's family) How do you let clients know you are going on vacation?
Out of office messages differ depending on whether you are sending them within or outside the company. The language you use and the information you provide can also depend on the workplace environment. Here are three out of office message examples that illustrate these differences.

Let’s be real, the majority of the thousands of emails you return to after being O.O.O. will be spam and salesy marketing drivel – any legitimately important emails will probably get lost! Unless you’re Barack Obama, just send it when they’re back.
The key to a good note is to let the person feel that you are really thinking of them. A good note keys into the person it's being sent to and reflects a special connection. (If you're writing to someone you don't know well, this is even harder. But I'll get to that later.) 1. Don't write the note when you haven't got a lot of time to think and ...