Exercise $4\mathrm{.}23$ Model the following business process at a supplier.

After a supplier notifies a retailer of the approval of a purchase order, the

supplier can receive an order confirmation, an order change, or an order

cancelation from the retailer. It may happen that no response is received at all. If

no response is received after $48$ h$,$ or if an order cancelation is received, the

supplier will cancel the order. If an order confirmation is received within $48$ h$,$

the supplier will process the order normally. If an order change is received

within $48$ h$,$ the supplier will update the order and ask again the retailer for

confirmation. The retailer is allowed to change an order at most three times.

Afterwards, the supplier will automatically cancel the order