How to Update Your Address Book in Outlook

To update your Global Address Book in Outlook first go to "File" then click "Account Settings" and then click "Download Address Book"

Ensure that the "Download changes since last Send/Receive" box is checked and then click "Ok"

Let the task run and then you should have an updated address book with any new contacts that were requested made.

To use those new contacts you may need to empty your auto-complete list (Which recommends names as you type them in any of the fields of an email) to do that click "File" and then "Options" then select "Mail" and scroll down to "Send Messages" and click "Empty Auto-Complete List" as pictured.