Couple of ways.
1. Change the view on the Contact folder to Category
(View > Current View
Category). Then go to View > Current View > Customize
Current View > Group
By > In the Select available fields change to All Contact
fields > In Group
items by change to "Private" > OK > OK. In the Contact
folder drag the
Private Yes row and drop it on the Private NO row (as you
drag onto the
Private NO you should see a pop up label which tells you
what field will be
changed). To reset the view go to View > Current View >
Define View > Reset
2. Export the Contacts to Excel change the Property of
the Private Column
to "False" and then import back in.