Delta flight change fee depends upon the costs and subscription purchased by the customer and the time in which the change request received. here is the full structure of the Delta flight change fee which shows all the fees to change Delta flights. Booking canceled/changed within 24 hours No fee; only fare difference paid No fee. After the time span of 24 hour period Not allowed fee of $200-&500 and the fare difference amount No fee.
https://airlinespolicy.com/flight-change-policy/delta-flight-change-policy/
