You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, Good Morning. How may I guide you?

USER: I want to travel from LAS to DFW.

ASSISTANT: Can I know your preferable dates?

USER: My preferable dates are from 09/21 to 09/23.

ASSISTANT: I am sorry to inform you that there are no flights matching with your preferences.

USER: That's ok. Thank you.

ASSISTANT: Thank you. Can I know your name?

USER: My name is Scott Green.

ASSISTANT: Thank you.