I discovered a cool feature in the Malaysia Airlines app (on Android at least) under Manage Your Booking. If you search for a booking and scroll down to the bottom, there is a See Receipts link. When you click on it, you see the leg(s) of your booking with the 13 digit ticket number.
I changed a OWA yesterday and hadn't received an email confirming reticketing. When I clicked on See Receipts, the new leg showed an error message while the existing legs had the old ticket number. I sorted out the ticketing issue this morning and received the email. On returning to MMB, the new ticket number is now showing up against all the legs of my booking.

I changed a OWA yesterday and hadn't received an email confirming reticketing. When I clicked on See Receipts, the new leg showed an error message while the existing legs had the old ticket number. I sorted out the ticketing issue this morning and received the email. On returning to MMB, the new ticket number is now showing up against all the legs of my booking.

