Yes, you can change your flight on the same day with Delta, depending on availability and fare rules.
Delta Change Flight Same Day Confirmed and Same-Day Standby option for eligible flights. With Same-Day Confirmed, you can change to a different flight on the same day for a fee. Same-Day Standby lets you wait for an earlier flight on the day of travel. Both options have specific criteria and fees, so it's recommended to check Delta's official website or contact their customer service for details and assistance on changing your flight on the same day.