This endpoint creates an addendum to a finance agreement. An addendum is a document that is
attached to the original finance agreement that outlines certain information that was
added or changed.
The request accepts the limited subset of Application fields that
can only be modified after e-signature by creating an addendum.
Similar to the update application endpoint, some or all of the fields can be included in the
request, in keeping with the “just send what you need changed” approach
outlined in RFC 7396.
If there is ever a scenario in a provider's worflow that has them altering information
on an application after their patient has signed their agreement but before they have
received their product/service, an addendum to the agreement must be created stating
that the patient knowingly made changes to their account.
If the financeAmount does not increase due to the changes made in the addendum,
the patient does not have to be contacted for the addendum to be applied, and the changes
will be reflected on the application immediately. An addendum PDF will be generated
and retained permanenlty on the server.
However, if the financeAmount increases even by a penny, the patient must be notified
and the addendum will require a signature before it can be applied.