Navigate to Gmail (https://gmail.com)
Click the settings cog in the top right
Click 'See all settings'
Scroll down to the bottom of the page to the section titled 'Vacation Responder'
Configure / remove your out-of-office settings as desired
Note: For further guidance on how to configure this, please click here
Open the 'Gmail' app
Select the three horizontal lines located in the top left of the screen
Scroll all the way down and select 'Settings'
Select the account you would like to set an out-of-office reply for
Scroll down to and select 'Out of Office AutoReply'
This can now be configured / removed as desired
Note: For further guidance on how to configure this, please click here