You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I aid you at this moment?

USER: Amy Lewis here. I want to travel from PHL to DFW for attending a business meeting. Can you please help me for booking the flight ticket?

ASSISTANT: Yes, I am happy to help you. Can you please let me know your dates of journey?

USER: My departure date is 08/02 and return date is 08/04. Make sure my price limit is 500.

ASSISTANT: Sorry Lewis, there is no flight to your destination on preferable dates. Thank you for reaching out here.

USER: Thank you for the information.

ASSISTANT: You are welcome.