I did purchase the new ticket for $900. And yes, 100% my fault I lost my passport (well, actually it wasnt since it was stolen, but, willing to take responsability for that regardless!)
I was prepared to pay a change fee and difference in fare, I was dissppointed that Delta did not charge me $150 and the difference from my original ticket - $800, and the new ticket I purchased, $900. According to their own terms and conditions, it should have cost me $250 ($150 change fee, $100 change in fare.) But they calculated the change fee based on a RT ticket, since that was what I purchased, which is how they came up with the $1400.
Same seat, same flight - I could pay $900 or $1400, so of course I opted for the $900 new ticket versus the $1400 "change fee: ticket. It just doesnt seem fair!
And I am Medallion (just silver though)