I have a few segments left on an AONE5 ticket on BA stock. Called BA res and made a date change to a CX BOM-BKK segment.

I'm sitting in the Wing, so I went up to the counter to see if they could "sticker" the flight coupon to show the new date/time. She looked up the reservation and confirmed the date change in CX's res system, but insisted that she couldn't sticker a BA ticket and that it's not required anyways.

Does this sound right?