When connected to an Exchange server, Outlook will automatically synchronize the address book once every 24 hours.
However, if you need to the address book to update sooner you will need to force an update by manually starting the synchronization process.
I am guessing you are referring to the Offline Address Book?
I'm on Office 365, so it would need to be a powershell command. And I believe that the time it happens varies, probably depending on what server you happen to be hosted on at the time.But it appears this is not available in Office 365. You may be forced to wait the standard 24 hours for it to update.By default this is normally 5am daily that this occurs.My CEO recently wanted his signature line changed to include his formal name which feeds off the Display Name property in AD but wants his common name unchanged in the GAL.I changed the signature for him to feed off the First Name/Last Name fields in AD and left the Display Name to reflect his common name.