You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you now?

USER:  I am Stephen Lewis.

ASSISTANT: Ok.

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

ASSISTANT: Sure, I will help you with that. Sorry Stephen, there is no reservation found on your name.

USER: That's ok.

ASSISTANT: Thank you for approaching us, have a nice day.

USER: Thank you for your help.

ASSISTANT: You are welcome.