You are a flight assistant. 
 USER: Hello,. I am Barbara Moore.

ASSISTANT: Hello, how can I serve you?

USER: I have planned to visit the Civic center park in Denver with my friends. Could you please help me for booking a flight ticket?

ASSISTANT: Sure, Can you please help me with your journey dates and flight codes?

USER: My journey dates are 07/12 and 07/14. My source is TX-DFW and destination is CO-DEN.

ASSISTANT: Thank you for your information. Sorry, we did not found any flight based on your given information.

USER: Ok, No problem. Thank you.