Make BPMN diagram using camunda developer. Use expanded sub-processes as part of the solution. Use attached events for exception handling. Treat the Customer Pool as a black box. Identify any items that would be collapsed sub-processes and call activities.

An order handling process starts when an order is received. The order is first registered. Next, an availability check is performed and a purchase order response is sent back to the customer. If any item is not available, the customer must be notified and any processing related to the order must be stopped. Any time after the order has been registered the customer can send a 'purchase order cancel request'. If a cancellation request is received the process is interrupted, the cancel order request is handled and all processes are terminated. The customer may also send an 'address change request' after the order has been registered - in this case, the address change will be performed without interrupting the process.