Originally Posted by jrl767

I think OP could make the case that change of operating carrier from one regional affiliate to another was transparent ("I didn't pay attention to that, the flight number is still in the 3000-7000 series"), but the mainline-->regional change is much more evident (explicit note stating "operated by Delta Connection carrier")because at that point OP is playing the SDC lottery with available inventory (for coach) or seats (for F); depending on when OP is traveling (e.g., holiday, school break, etc) that could be problematic in real time

that said, OP's "chance I might need to cancel completely" remark suggests that waiting is probably best, since making the allowed change now takes the option of a no-penalty refund off the table