You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Benjamin Miller.

ASSISTANT: Miller how may I assist you?

USER: Actually, there is a small change in my planning. So, can you help me to change my reservation?

ASSISTANT: Sorry, there are no reservation on your name.

USER: Oh! that's fine.

ASSISTANT: Thank you for choosing us.

USER: Anyway, thank you for your supportive service.

ASSISTANT: It's my pleasure.Have a nice day.