You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you today?

USER: Can you please help me to change my existing reservation?

ASSISTANT: Sure, may I know your name?

USER: I am Nancy Lee.

ASSISTANT: Ok, please wait for sometime.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found on your name.

USER: Ok, not an issue. Thank you for checking.

ASSISTANT: Thank you for reaching us.