In general, Outlook will automatically update the Offline Address Book (OAB) for Exchange accounts once every 24 hours.
When it didn’t or when you want to make sure you do have the latest OAB available, you could manually trigger an update by following those steps:
Open your Outlook.
From the top navbar click on “Send / Receive” tab.
Click on “Send/Receive Groups” from the drop down menu.
Select Download Address Book (as shown below).
5. Make sure to follow the settings as shown below and click OK
6- Once completed, your address book should reflect latest changes/updates.