You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I would like to book a ticket from IAD to DTW, can you please help me out?

ASSISTANT: Sure, I am here to help you for this. Could you please share me your trip dates?

USER: I am travelling on these dates Sept 20th and 22nd.

ASSISTANT: May I know your name please?

USER: Cynthia Rodriguez here.

ASSISTANT: Do you have any requirements regarding your journey?

USER: I prefer departure time in the evening.

ASSISTANT: Is there any other specifications?

USER: I need single connected flight.

ASSISTANT: Sorry for inconvenience, no flights are found with your requirements.

USER: Ok no problem, thank you for your services.

ASSISTANT: Thank you very much for contacting our agency.