Use Visio to draw this problem to draw an activity diagram with swimlanes.
Suppose that a customer wants to return an item he/she bought through a mail order. In order to do so, the customer first calls the company's service department to request a return. The service employee verifies whether the return is valid; and if so sends a return number. Then the customer can ship the item with the given return/claim number. The company's warehouse receives the item and restocks it. The item now becomes available for sale again. The company's accounting department credits the customer's account.