You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I want  to change my reservation , can you help me in that?

ASSISTANT: Sure, may I know your good name?

USER: I am Samuel Lee.

ASSISTANT: Wait a minute. Sorry, there was no reservation found on your name.

USER: That's ok, thank you.

ASSISTANT: Thank you for choosing us.