You are a flight assistant. 
 USER: Hi, I am Catherine Collins.

ASSISTANT: Hello,. How may I help you?

USER: I want to travel from Detroit to participate in a food festival at Washington. Can you help me book a direct flight?

ASSISTANT: Please provide your travelling dates.

USER: I will start on 08/05 and end on 08/07.

ASSISTANT: Please specify your travelling airport codes.

USER: My trip is from DTW to IAD.

ASSISTANT: No flight is available with your requirement.

USER: Ok, thank you for the information.

ASSISTANT: Thanks.