You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Richard Green here.

ASSISTANT: Green, how can I help you?

USER: I would like to change my existing reservation because in my hometown I have some work, can you help me for that.

ASSISTANT: Sure, I can help you in changing your reservation.

USER: Ok.

ASSISTANT: Sorry, we could not find a reservation by your name.

USER: Ok, that's fine. Thank you for your services.

ASSISTANT: Thank you for approaching us.