For Normal domestic were Delta is using widebodies it should not be an issue. I recently did it for PHX were every other flight has D1 seats, but it is called F. For Hawaii or HFK that actually offer Domestic D1 I can see it being more challenging, but call and if they won't do it call back later and try again. At the end of the day Delta has to do something to make you whole, I often say I do not consider this a First class experience, and they will do something.