Ambassador, British Airways; FlyerTalk Posting Legend
Join Date: Apr 2012
Location: Leeds, UK
Programs: BA GGL/CCR, GfL, HH Diamond
Posts: 43,253
In fact, if you look at your bag tag your original booking PNR doesn't appear on it but your "new" BA internal one does. The BA internal one appears a few days before the first flight when it syncs with the airport systems. If you have myflightsapp you will be used to the notification appearing a few days before your booking.