You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: Could you please help me in  booking a ticket from IAD to DFW where I have a concert to attend.

ASSISTANT: Sure, may I know your name?

USER: My name is Patricia Harris.

ASSISTANT: Can you please let me know your journey dates?

USER: My itinerary travel dates are as follows Apr 23 and Apr 25.

ASSISTANT: Do you have any specifications?

USER: I would like to board a direct flight.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Sorry, there were no flights found on your route.

USER: No issue, thank you for the information.

ASSISTANT: Thank you.