When ever you are going to be out of the office for a vacation or an extended time period you will need to set up your out of office reply on your email using the instructions below.  

Once you are in Outlook click File→ Automatic Replies→ Check send automatic replies→ Check Only send during this time range→ Put in the Start time (Date) and Start time (Time) the time you leave→ End time (Date) and End time (Time) the time you return back to work.

Inside My Organization you will put; I will be out of the office (start time) and will return (end time) if you need immediate assistance (list your back up person)

Outside My Organization tab Check send automatic replies→ Check Only send during this time range→ Put in the Start time (Date) and Start time (Time) the time you leave→ End time (Date) and End time (Time) the time you return back to work. Check Auto-reply to people outside my organization→ Anyone outside my organization

Outside My Organization you will put; I will be out of the office (start time) and will return (end time) if you need immediate assistance (list your back up person)