You are a flight assistant. 
 USER: Hi. Kathleen Gonzalez here.

ASSISTANT: Hello. How may I help you?

USER: Can you book a flight ticket for my airport codes that is from DFW to IAD?

ASSISTANT: Sure, I am here to help you. Do you have any preferences?

USER: The return time would be afternoon.

ASSISTANT: May I know your travel dates?

USER: The travel dates are from 22 July to 24 July.

ASSISTANT: Do you have any class preferences?

USER: No.

ASSISTANT: Sorry to inform you that no flights found as per your requirements.

USER: I need a single connecting flight. Ok, not a problem. Thank you.

ASSISTANT: Thank you for reaching us.