I purchased a "refundable main" ticket that advertised free same day changes and free cancellation with refund back to mode of purchase (i.e. credit card instead of eCredit). As my plans were very "iffy" this was appealing to me. I called Delta (1 hour hold time) the day before the trip to inquire up to what point I could cancel - at this time option to cancel was showing in the app. About 2 and a half hours before the flight was to depart the option to cancel disappeared from the app. Also could not cancel by logging into my account online. It did show ability to change flights but once I pushed this option I received the "no flights available" message. I was unable to get through to Delta by phone or chat. About an hour before flight time a later flight time was showing available so I picked this (only to extend the time available to cancel the flight in hopes that my call would be answered - over 2 hours on hold at this point). A phone rep was finally available 2 minutes after the new, later flight departed. Now my ticket value shows as a eCredit. I did ask the phone rep to request a refund. She said it will take 1-2 billing cycles if a refund is approved. So just a warning- need to cancel more than 3 hours ahead of departure it seems and ability to select a new flight may or may not be there.