If you retrieve your contacts from social network sites and add them to your address book, the same contact may be displayed more than once. You can merge identical contacts so they will appear only once.
Slide your finger left on the display to open the main menu. Tap Contacts.
Tap the required contact.
Tap Add Link.
Tap the required contact to merge the contacts.
Slide your finger upwards starting from the bottom edge of the display to return to the home screen.