Applying a change returns the fields that actually changed, which is not necessarily what was asked for. Compare the response against your request rather than assuming success.
Maintenance
Maintenance Overview
Change a boarded merchant’s details at the processor that holds it
Maintenance changes a merchant’s record at the processor it was boarded with. Not every processor exposes a maintenance interface, and those that do accept only some fields — so check capability first, validate the change while the user is still typing, and apply it last.