You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I aid you?

USER: As we postponed our vacation, can you help me to change my existing reservation?

ASSISTANT: Sure, I am here to serve you? May I know your name please?

USER: Sure, my name is George Davis.

ASSISTANT: Ok, Just a minute, I will check and revert you.

USER: Ok.

ASSISTANT: I am sorry to say there is no reservation found for you.

USER: That's Ok. Thank you.

ASSISTANT: Thanks for reaching us today. Have a good day.

USER: Thank you.