Originally Posted by ethernal

I believe Delta upfares are only free to change the class of service, not to change between in-cabin fare types. So you can buy up to an F fare at no change fee but I don't believe you can change from an E to a Y ticket. Logic concludes that if you could do that, one would just always upfare an E ticket to a Y ticket to turn it into a fare you can do a change (for a fee) on if you needed to make a change...