**Need help with bpmn notation**

A restaurant chain submits a purchase order (PO) to replenish its warehouses every Thursday. The restaurant chains procurement system expects to receive either a PO Response or an error message. However, it may also happen that no response is received at all due to system errors or due to delays in handling the PO on the suppliers side. If no response is received by Friday afternoon or if an error message is received, a purchasing officer at the restaurant chains headquarters should be notified. Otherwise, the PO Response is processed normally.