You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, How can I assist you?

USER: I am Jeffrey Wilson from Washington. I am planning to celebrate my birthday in Detroit, so please book a flight ticket within a price limit of 1000.

ASSISTANT: Sure, May I know the travel dates?

USER: I would like to fly on 07/13, return on 07/15.

ASSISTANT: Please help me with your journey codes.

USER: My source and destination airport codes are DC - IAD, MI - DTW.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Sorry, No flights found with your chosen dates.

USER: No problem, thank you.

ASSISTANT: Thank you for availing us.