Change the Default Address Book in Webmail/OWA

In the upper right hand corner click on Options>See All Options

Sign out Fleming, Michael. Find someone, options: Options, set automatic replies..., create an inbox rule... see all options...

On the left click Settings>General

outlook webapp. mail - options. Account, organize e-mail, groups, settings (1), phone, block or allow. mail (2), calendar, general, regional. E-mail signature.

Select Contacts

mail, calendar, general: e-mail name resolution. When resolving names, check first in: global address list, Contacts.

Finally click Save in the lower right corner