You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you?

USER: Can you please help me in changing my reservation as the audio launch which I want to attend got postponed?

ASSISTANT: Sure, let me know your good name please.

USER: I am Rebecca Lee.

ASSISTANT: Ok, please wait a while.

USER: Sure.

ASSISTANT: Unfortunately there is no reservation found matching your name.

USER: It's ok, thank you for your kind information.

ASSISTANT: Thank you for consulting us.