You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: I am Robert Moore. I am planning to change an existing reservation, due to health issue. Can you please change my reservation?

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

USER: Thanks.

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

USER: Sure, I will wait.

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

USER: That's fine.

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

USER: Thank you for your service.