You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I have to attend a workshop on waste management, please book my ticket from ORD to IAD.

ASSISTANT: Sure, please tell me your trip dates.

USER: My trip dates are 12/08 and 12/10.

ASSISTANT: Ok, may I know your name please?

USER: My name is Nicholas Turner.

ASSISTANT: Sorry, there is no plane on your requested travel dates.

USER: It's ok, thank you.

ASSISTANT: Thank you.