Mute Outlook app on iPhone during holidays
If you do not want to receive notifications for the week you can simply disable notifications in the notification center. 

Steps


Go to Settings (the settings app for the iPhone)
Tap on Notification Center
Find Outlook and Tap on it
Tap the slider next to Allow Notifications to turn it off. 


This will turn them off so you do not receive any notifications. To turn them back on follow these steps.


Go to Settings (the settings app for the iPhone)
Tap on Notification Center
Find Outlook and Tap on it (This time it will be under the do not include section)
Tap on the slider next to Allow Notifications to turn it on.