You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I assist you at this moment?

USER: Robert Turner here. Can you please help me in changing my existing reservation?

ASSISTANT: Sure Robert Turner, I am happy to help you with that.

USER: Thank you.

ASSISTANT: Please wait a moment to check your reservation status.

USER: Sure.

ASSISTANT: Sorry Robert Turner, no reservation has found under your name to change.

USER: Not a problem, thank you.

ASSISTANT: Thank you for choosing us, have a good day.