Dear P'Kook,
First of all, i really apologize for inconvenience.
I'm very sorry for my overlook. But we immediately action when he arrived transit counter. I already say sorry and inform staff to take a good care with him. Staff informed him about upgrade will be confirm at boarding gate cause passenger under decide at check in counter at that time.
Finally,our gate staff confirmed for upgrade him after check in counter closed
Sorry again for inconvenience.