You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I want to travel from EWR to DTW. Can you help me to book a flight ticket?

ASSISTANT: Sure, may I know your name please?

USER: Ryan Collins.

ASSISTANT: Can you please share on what dates you are willing to travel?

USER: I want to travel in the flight on Jan 18 and Jan 20.

ASSISTANT: Please provide your specifications.

USER: I prefer to travel in business class.

ASSISTANT: Unfortunately there is no flight found with your given information.

USER: That's ok. Anyways, thank you.

ASSISTANT: Thank you for choosing us.