Send only the fields that change. Fields you do not send stay as they are.

Each business, owner, address, phone and credit score in GET /end_users/{id}/details has a heron_id. To change one of them, send its heron_id with the fields you want to change. To add a new one, send it without a heron_id. The business must always include its heron_id, if the deal already has a business.

To remove a value you set, send null. For a list, [] removes the whole list. To remove one item from a list, send the full list again without that item, because a list replaces the previous one.