Samsung Galaxy S4 User Manual page 124

Facebook account login name might differ from a corporate email
account login because they are maintained separately and for
different groups of people.
This device can synchronize with multiple accounts. When you
synchronize your phone with those accounts, each account creates a
separate contact entry in the Contacts list.
If one of your contacts (Amy Smith) has a regular email account that
you maintain in Gmail, but also has a Facebook account under her
maiden and married name, as well as a Video! chat account, when
you merge those accounts into your Contacts list you can join all of
her entries and view the information in one record.
Joining contact information makes sending messages easy. You can
select any account email address or information all from one screen,
versus searching multiple, individual screens to locate the desired
account information.
Next time you synchronize your device with your accounts, any
updates contacts make to email account names, email addresses,
etc. automatically update in your contacts list.
1. From the Home screen, tap
2. Tap a contact name (the name you want to link to another
entry) to reveal the Contact entry's Overview Screen.
Note: Typically this is the same contact with a different name or
account information.
3. Press
117
and then tap Link contact.
.