Search for a referrer to connect to a referee, just using the referrer's name, entered by the referee. If we don't have an exact match for the referrer's name we'll respond with a 404 or 400. The referee can change the name and/or enter an email address of the referrer to find an exact match.
In a non-exact match we will not return a payload response and we'll also set the foundMultipleReferrers parameter in the root of the response, to indicate that the search needs to be narrowed (i.e. ask for an email address or possibly prompt for a more verbose name). The exact narrowing strategy is up to the client.
If there is no payload and no foundMultipleReferrers set, the client should prompt for a fresh search.
When an exact match is found, the payload contains the customer ID, flow token and the offer.