Identify ambiguities or omissions in the following statement of requirements for a rental car reservation system:
Customer specifies start and end dates for the car rental, and where they would like to pick up and return the car.
The system then presents the customer with a list of available cars and prices. The customer selects the desired car from the list.
The system then prompts for a credit card number and expiration date. Customer supplies necessary credit information. System then asks customer to confirm reservation by pressing button.
If customer confirms, system issues a confirmation number that customer can use to retrieve car at start date.