1.  Click Contacts > Contact List


2.  Look to the left side of the page, where the Advanced Filters options are located


3.  Under the "Search Group" drop-down menu, select "Duplicates by name" or "Duplicates by email", and hit Search.



If you want to merge the contacts, you would need to select the two contacts, and then from the Actions drop-down, select the "Merge Contacts" option.