You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: I want to change my existing reservation. Can you help me with that?

ASSISTANT: Sure, may I know your name?

USER: Yes, myself Steven Robinson.

ASSISTANT: Sorry, there is no reservation found under your name.

USER: That's ok, may be it is already changed. Thank you for assisting me.

ASSISTANT: Thank you for reaching us.