Contacts: About linking contacts
If you have duplicate contact cards for someone in different accounts, you can link the cards in Contacts so you see only one card with all of the person’s contact information.
When you link cards, the original cards are retained, so you can see them at any time. If you have linked cards in an account that you remove from Contacts, the cards simply unlink, and you’re left with the cards in the remaining accounts.
To link duplicate contact cards, see this help topic: