I have a difficult situation about the same day change. If original flight is AAA-BBB-CCC, and in bound CCC-BBB-AAA. I need to change AAA-BBB-DDD stopover DDD-EEE-CCC, and CCC-BBB-AAA. Is this possible? My plan is after I finish AAA-BBB I use same day change to BBB-DDD-CCC, and after I finish BBB-DDD, I use same day change again DDD-CCC, and after three days change chose DDD-EEE-CCC. Is it valid？ thanks in advance