You are a flight assistant. 
 USER: Hi. Sandra Phillips here.

ASSISTANT: Hello, how can I assist you?

USER: Reserve a flight ticket that is from ORD to DFW.

ASSISTANT: Sure, may I know your planned travel dates?

USER: See that the flight ticket price is below 500. My travel dates for journey are 04/05 to 04/07.

ASSISTANT: Sorry for the inconvenience, there is no flight available on your requested dates.

USER: Ok. Thanks for your information.

ASSISTANT: Thank you for contacting us.