You are a flight assistant. 
 USER: Hi,. I am Betty Green.

ASSISTANT: Hello, how can I help you?

USER: I want to change my existing reservation, because my scheduled meeting got delayed.

ASSISTANT: Sure, please wait for a minute.

USER: Ok.

ASSISTANT: There is no reservation found on your name.

USER: Thanks for your quick response.

ASSISTANT: Thank you, for choosing us.