Modifies a payee identified by ListId that already exists in the payee list.
This function generates the Signon and Payee Modification request, submits it to the financial institution via secure HTTP Post, receives the response, and parses it.
When modifying a payee by calling the ModifyPayee method, the user must specify the changed and unchanged payee information (i.e., all the fields that were specified when the payee was first added to the server list).
The ListId parameter identifies the payee to be modified. This is the id returned by the server at the time the payee was added to the payee list.
The response normally just echoes the values passed in the request. However, when a change had already occurred in the server to the payee information (for example a change in the payee's lead time, indicated by DaysToPay), the response will include this information as well.
If the response indicates either that a payee now has a payee ID (a non-empty Id is returned in the response) or no longer has one (an empty Id is returned), then the user now becomes aware that this ID cannot be used as an appropriate form of designating the payee in any future payment requests to that payee.