Wandering over from the AA side to DL forum to ask a question that googling didn't quite answer my questions. I am thinking of flying DL out of ORH since their flight is later in the day than AA's which works for my schedule. Plan to booking using DL miles. I may not need to do this trip at all (long story)/

Questions:
- Can I cancel for free before the flight and do miles and tax money come back to me? I read somewhere free cancellation is only within 24 hours of booking. Exactly what are the specific I need to be aware of here.
- Any difference if I book a basic economy fare vs. economy?

I have no DL status and no DL credit cards at this time.

Thanks in advance.