Many airlines (at least here in the U.S.) have flight numbers that use different aircraft for different legs of the flight. For example, Delta 158 uses a 747-400 from Incheon International in Seoul to Detroit, then an A320 from Detroit to Boston a couple of hours later. This got me to wondering what happens if an earlier leg is delayed such that it's arriving around the time that the next leg is departing the same airport? In particular:
Will both flights use the same radio call sign? That is, will they both be "Delta 158" (ignoring the "Heavy" difference in this particular case?)
If they do use the same call sign, how do controllers know which one is talking, especially if they end up on the same frequency at some point?
It seems like this sort of situation would happen somewhat frequently, at least here in the U.S. where it's common for a given flight number to include multiple legs and for those legs to operate on different aircraft.
This question is related, but doesn't actually address this particular question: Why are some ATC call signs different than the flight number?