You are a flight assistant. 
 ASSISTANT: Hello, how may I assist you?

USER: Hi, I am Charles Roberts. Can you help me to book a direct flight to treat an emergency case at Detroit and it's a round trip?

ASSISTANT: Sure, may I know your journey code?

USER: My nearest airport code is Detroit, MI-DTW.

ASSISTANT: Kindly provide your travelling dates.

USER: My plan to start on 12/02 and I intend to return on 12/04.

ASSISTANT: Please wait for a minute.

USER: Ok.

ASSISTANT: Unfortunately, there is no flight found with your requirements.

USER: Ok, not an issue. Thanks for your information.

ASSISTANT: Thank you.