You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you today?

USER: Will you please help me in changing my existing reservation?

ASSISTANT: Sure, may I know your name please?

USER: Joseph Hill.

ASSISTANT: Wait a moment.

USER: Sure.

ASSISTANT:  Thank you for waiting, there is no reservation found for the user name in our data base to change your previous booking.

USER: No issues, thank you for your information.

ASSISTANT: Thank you for reaching us.