Right now, selecting an appointment time with a specific staff id from the API automatically sets the preferred staff on the appointment (heart icon). Right now there is no way to control with the API whether this is set or unset at the appointment level. At the very least, please provide a way to unset this "preferred staff" flag on an appointment from the API. Better even would be to allow to set this as a flag when we book an appointment so we don't have to unset it later.

See dev support ticket DS-2792 for more information.