If you are in the Wholinks panel you will see that each backlink is in a row, each of the columns gives its information. All except the last one, you will see two buttons, the yellow one is for editing and the red one for deleting.
Why would you want to edit the domain? Well, if you have added the links with the API you will see that they do not carry price information, so if you want to add it for information you can do it easily.
Just fill in / change the fields here and you are done.