You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: I would like to change my reservation, as my business meeting has been postponed. Can you please help  me with that?

ASSISTANT: Sure, I am here to help you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Sure, my name is Mary Allen.

ASSISTANT: Sorry, there is no reservation found under your name to change.

USER: Ok, no issues. Thank you for checking.

ASSISTANT: Thank you for choosing us.

USER: You are welcome.