You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I am Charles Carter have to attend a business meeting at Chicago, can you help me to book a direct flight?

ASSISTANT: Sure, may I know your travelling dates?

USER: Sure, my travelling dates will be 03/26 and 03/28.

ASSISTANT: Ok, may I know your airport codes?

USER: Yes, I want to fly from DCA and land on ORD.

ASSISTANT: Give me a minute.

USER: Ok.

ASSISTANT: There is a connecting flight with number 1000 in airline Frontier, the fare is 200.

USER: No, do not proceed with my booking as I need a direct flight.

ASSISTANT: Sorry, there is no direct flight on your requested dates.

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.