You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I help you?

USER: I am David Hill. I want to book a ticket from DTW to DEN, can you help me?

ASSISTANT: Sure, I will help you in booking the ticket. May I know your travelling dates please?

USER: My travel dates are June 01 and 03.

ASSISTANT: Do you have any other specifications?

USER: I want to return in the afternoon.

ASSISTANT: Sorry for this inconvenience, I could not find any flight with your requirements.

USER: No problem, thanks for checking.

ASSISTANT: Thank you for reaching us.