You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is John Smith.

ASSISTANT: How can I assist you today?

USER: I want to do some changes in my existing reservation. Can you help me for that?

ASSISTANT: I am here to help you, let me check your reservation status.

USER: Thank you.

ASSISTANT: Smith, I have not found any reservation by your name.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for contacting us and have a nice day.

USER: Welcome.