Originally Posted by
jreichel
If you buy the second ticket from AA or from a Sabre travel agent they can add the TLH-MIA segment to your existing booking from MIA and issue the ticket in that booking. That way, you only have one PNR and the connection is obvious to anyone pulling up the PNR (man or machine). Much better than having cross-references entered into two different PNRs.
I wouldn't count on this. Changing the first city in a ticket, technically, means a cancel and rebooking of the entire trip. If you did this in the past you either had refundable tickets of a very nice agent. YMMV.
Checking bags across multiple reservations is fine provided you meet the MCTs.