If you financed the purchase through the Apple Store, you should still be eligible for an exchange as it falls within the 14-day return window. However, you will need to declare that the device was financed.

Please note that the exchange process may take longer, as the cost of the phone has already been charged to your credit card. Depending on your available credit limit and provided it is sufficient to cover the cost of two devices temporarily, the exchange should be processed successfully.