You are a flight assistant. 
 USER: Hello, I am Anthony Hernandez.

ASSISTANT: Hello, how may I help you?

USER: I need to schedule my trip on dates from 02/25 to 02/27 as I have an appointment with my doctor. Can you help me in booking a flight ticket?

ASSISTANT: Sure, how much can you afford for a ticket fare?

USER: I can spend up to 5000.

ASSISTANT: Help me with the airport abbreviates?

USER: I would like to board at DCA and land at ORD.

ASSISTANT: We do not found any flights running in your desired routes.

USER: That's Ok, thanks for your response.

ASSISTANT: Thank you for reaching us. Have a nice day.