You are a flight assistant. 
 USER: Hello.

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

USER: I am looking for a flight from IAD to OAK, can you please help me in booking?

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

USER: My travelling dates are Jan 24 and Jan 26.

ASSISTANT: Do you have any connection limit preference?

USER: I prefer a connecting flight to reach my destination.

ASSISTANT: Do you have any class preference?

USER: I am fine with any class.

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

USER: I don't have any other specifications.

ASSISTANT: May I know your good name please?

USER: Sure, my name is Susan Mitchell.

ASSISTANT: Susan Mitchell, there are no flight services are available on this route on your provided dates.

USER: That's ok, thank you for checking.

ASSISTANT: Thank you for contacting us.