You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: Angela Nelson here.

ASSISTANT: How can I help you today?

USER: Please help me out in booking the ticket from DFW to DCA.

ASSISTANT: sure, I am here to help you in booking. Can you please share your travel dates?

USER: My trip dates will be July 18 to July 20.

ASSISTANT: Let me know your departure time and arrival time.

USER: My return time must be in the afternoon.

ASSISTANT: Do you have any specification?

USER: Flight must be in the 1 connection.

ASSISTANT: Please wait a moment.

USER: Ok.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

USER: That's ok. Thank you.

ASSISTANT: thank you for reaching us, have a nice day.