I will probably need to submit a missing Avios claim for a recent LAN flight. Mr W's Avios and TPs posted over a week ago (same booking) but nada on my account.

I don't have the boarding pass (don't ask!) and the webform on ba.com wants my ticket number. This is where it gets a bit complicated. I have all the paperwork from our booking BUT about a week out LAN rescheduled our flight to several hours later and as a result agreed to put us on an earlier service.

Is it likely that the ticket number will have changed as a result of that change? I don't know if that sort of change means a new ticket number, or they just update the details on the existing one. The PNR stayed the same.

Stupidly although I saved the email containing the new details, they were in the form of a link which is now dead. I can't get anything from LAN.com or checkmytrip.

Are there any other ways to look up a ticket number from a flight by PNR?