You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how can I help you today?

USER: I want to book a flight ticket to attend my father's retirement ceremony. Help me with the reservation.

ASSISTANT: Sure, I am happy to  help you for that. Can I know your name please?

USER: The retirement ceremony is at Washington DC - IAD and I want to start from Dallas, TX- DFT. I am Joshua Thomas.

ASSISTANT: OK, may I know the travelling dates please?

USER: Sure my Depart date is 19th Oct and Return date is 21st Oct.

ASSISTANT: Thank you, do you have any other specifications?

USER: I need a connection between my journey with a price limit 1000.

ASSISTANT: OK, can you please wait for a while , I will check with the availability and get back to you.

USER: OK, sure.

ASSISTANT: Thanks for waiting. We are sorry to say you that, we have not found any flights as of your given details.

USER: OK, thank you.

ASSISTANT: Thank you, have a great day ahead.