You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I assist you at this moment?

USER: Can you aid me to book a ticket from OAK to IAD?

ASSISTANT: Sure, I am here to help you. Can you please provide your journey dates?

USER: My travel dates are Oct 21 and Oct 23 respectively.

ASSISTANT: Do you have any connection limit preference for this trip?

USER: Make sure that I need a single connecting flight to travel.

ASSISTANT: Do you have any other specifications for this trip?

USER: My return journey should be in the morning.

ASSISTANT: May I know your good name please?

USER: Susan Smith here.

ASSISTANT: Susan Smith, there are no flight services are available on this route with your preferences.

USER: No issue. Thank you.

ASSISTANT: Thank you for contacting us.