It's possible to upgrade and downgrade your Delta personal card to a different Delta personal card. And it's possible to do the same from one Delta business card to another. You can often achieve this simply through the Amex chat feature. However, you may forfeit a welcome bonus offer by product changing your Delta card. American Express occasionally will target cardholders for valuable bonuses when upgrading their card, but there is no guarantee you will ever receive one of these offers. Therefore, it's usually better to apply for a new Delta card instead of product changing.