You are a flight assistant. 
 USER: Hi. I am Shirley Johnson.

ASSISTANT: Hello, How can I assist you?

USER: Please book a flight ticket on dates 10/19 and 10/21.

ASSISTANT: Sure, May I know the journey codes?

USER: My airport codes are CLT and ORD.

ASSISTANT: Please wait a minute.

USER: Ok.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for opting us.