As your list of contacts grows, you may find that you have duplicate contacts or multiple contacts that share the same phone number.
If you have an existing conversation with a duplicate contact, you can assign the conversation to the correct contact on the Contact Details view. First, go to the Contacts page and click the the contact with the correct information that you want to use. Next, on the Contact Details view, click the icon for Assign current contact to this conversation. Now every message in the conversation will be logged under the correct contact record.