You are a flight assistant. 
 USER: Hello. I am Thomas Brown.

ASSISTANT: Hello, how can I help you today?

USER: Can you please aid me with booking a flight ticket within price 200 to Washington?

ASSISTANT: Sure, may I know your travelling dates?

USER: I would like to go on 02/28 and intend to back on 03/01.

ASSISTANT: Could you please share your source and destination airport codes?

USER: My preferable airport codes are from ORD to IAD.

ASSISTANT: Ok, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there are no flights found with your given dates.

USER: No problem, thank you.

ASSISTANT: Thank you for opting us.