You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Could you book my ticket in a direct flight?

ASSISTANT: Sure, please provide your travel dates.

USER: I want to travel on Oct 28 and Oct 30.

ASSISTANT: May I know your airport codes?

USER: I want to travel from DEN to BOS.

ASSISTANT: Do you have any preferences?

USER: I prefer economy class.

ASSISTANT: May I know your name?

USER: Jonathan Williams here.

ASSISTANT: Is there any time concern?

USER: No.

ASSISTANT: Sorry to inform you that there is no flights found.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us.