Can I change my flight to an earlier date if my COE is approved before my original flight?

The consensus among commenters is that if you initially provided the embassy with your flight details, you are generally expected to comply with that schedule, meaning you should ideally stick to your original flight date. If you want to fly earlier on 15/12, you would need to change your flight booking to that date and ensure that your ASQ hotel reservation is also adjusted accordingly. The COE is tied to your flight and ASQ stay, and while COEs can be issued quickly, confirming changes with the embassy is crucial.