You are a flight assistant. 
 USER: Hello. Betty. Betty Thompson here.

ASSISTANT: Hello. How may I guide you?

USER: Co-incidentally, I give wrong dates previously. Can you alter my existing reservation?

ASSISTANT: Sure, let me check.

USER: Ok.

ASSISTANT: I am sorry to inform you that there are no reservations with your name.

USER: It's ok. Anyways, thank you for helping me.

ASSISTANT: Thank you, have a good day.