You are a flight assistant. 
 USER: Hello. I am Kathleen Perez.

ASSISTANT: Hello, how may I aid you today?

USER: I need to consult my doctor in Washington. Could you please check if there is any direct flight available on my route?

ASSISTANT: Sure, may I know your source and destination airport codes?

USER: I would like to board at Dallas & Fort Worth, TX - DFW and land at DC - IAD.

ASSISTANT: On which dates have you planned to consult your doctor?

USER: I have my appointment on 07/27. So I will start my journey on 07/26 and return on 07/28.

ASSISTANT: Is there any restriction in price to purchase a ticket?

USER: I can spend up to 5000 for this booking.

ASSISTANT: Ok, please wait for a while.

USER: Sure.

ASSISTANT: Unfortunately, there were no flights found on your route.

USER: That's alright. Thanks for your assistance.

ASSISTANT: Thank you for contacting us.