If you are going to be out of the office, you can setup Outlook to send an automatic reply to incoming messages.
Windows 7 (Outlook 2010) or Windows 10 (Outlook 2016)
In Outlook, click File > Automatic Replies (Out of Office)
From there, you can enable or disable automatic replies or set a date/time range if you wish. There are two tabs, "Inside My Organization" and "Outside My Organization". Once you enable Out of Office replies, you'll able to customize internal and external replies. It can be helpful to include the dates you'll be out as well as contact info for a backup or supervisor in the event the person trying to contact you needs more urgent help.