A family member is flying AA from the Caribbean to MIA Friday afternoon, the flight operates noon to 4pm. Once in MIA, they will choose whether to fly to DFW or EWR.

They have purchased a separate ticket from MIA to DFW for about 730pm. No problem there.

However, they are also purchased a MIA-ORD ticket for Friday morning that (prior to that flights's departure time) they will do a same day flight change to a Friday evening flight.

Question; On Friday morning, when they use same day flight change to move the MIA-EWR morning flight to an evening flight that is at the same time as their purchased ticket from MIA to DFW, what will happen? Will AA cancel one of the purchased tickets?