You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

USER: Due to some emergency, I need to change my existing reservation. Can  you help me with that?

ASSISTANT: Sure, I will help you with that changing reservation. May I know your name please?

USER: I am Dennis Hall.

ASSISTANT: Please wait for a moment, let me check your previous reservation status.

USER: Sure.

ASSISTANT: Thank you for waiting.

USER: Ok.

ASSISTANT: There is no reservation found on your name in our reservation list to change it.

USER: It's ok, not an issue. Thank you for the information.

ASSISTANT: Thank you for reaching us, have a great day.