It's possible to set card + saved_card option thus enabling buyer to select one of saved card or rather enter a new card.
Simply replace whitelisted_pan_tokens with supported_payment_methods and you are free to add card option to previously saved cards.
Setting supported payment method as: supported_payment_methods:3cfb7f1df0ef7ef707ad213e4850219ed4b4553a96a68b6430359d002acdcafd,card
will result in:
- preselected payment with card represented by a token
3cfb7f1df0ef7ef707ad213e4850219ed4b4553a96a68b6430359d002acdcafd - an option to pay with a new card