You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How can I help you?

USER: I need to book a flight ticket from ATL to DFW, Can you please help me for booking?

ASSISTANT: Let me know your travel dates.

USER: I would like to travel on 06/17 to return on 06/19.

ASSISTANT: Do you have any preference?

USER: I need a normal cost airline.

ASSISTANT: Let me know your name.

USER: Donald Green.

ASSISTANT: Sorry, no flights found for your travelling dates. Thank you.

USER: Ok, no problem. Thanks for your information.