You can't. This is not a feature of osTicket at this time.That being said there is a great post by forum user @[deleted] that describes how they run a nightly script to synchronize their AD/LDAP data with their users. He also has a repo at github
for his solution. I would recommend searching and/or looking at: http://forum.osticket.com/d/discussion//ldap-fields-physicaldeliveryofficenamehttps://github.com/Chefkeks/osTicket-Addons