You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is Paul Collins.

ASSISTANT: How may I help you?

USER: I would like to travel from IAD to PHX, could you help me out?

ASSISTANT: Sure, please tell your travel date.

USER: My preferable dates are from 09/20 to 09/22.

ASSISTANT: Sorry, no flights available at this moment.

USER: That's ok. Thank you for your time.