Find ticket number of flight when booking with American Express

Recently I booked a flight with my American express points and annual bonus however on receipt I was only given a booking reference number

If you ever need to claim missing miles with your alliance or carrier they need a 13 digit number on your boarding card ( sometimes not ! ) and the flight number and date

Anyome else needing this ticket number you can just reply to the American express booking number and they email it to you