Firstly look to see if there are flights via Delta that appeal to you. Then call and ask them to switch you because of the 2 schedule changes. Most agents will be able to do this with ease. If there is not a better schedule on Delta but on another airline you can ask them about putting you on that flight (a rather small chance of this happening). If they say no to that inquire about a refund and go about purchasing the schedule you want on your own.