Scheduling and Reservation with Process Order API.....

Process order API can be used to perform scheduling actions on order lines. Scheduling
actions include:

1. schedule
2. unschedule,
3. reserve and 
4. unreserve.

The schedule_action_code field provided on the order line record (line_rec_type) can be used to provide the action which needs to be performed on the order line.

Reservations can also be performed by passing the reserved_quantity on the order line record. You do not need to send in the schedule action if reserved_quantity is passed.

Process Order API will also automatically schedule or re-schedule the lines if the schedule_ship_date or schedule_arrival_date field is passed or updated respectively.