You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you today?

USER: Samuel Martin here. Please book my ticket from ATL to DCA.

ASSISTANT: Sure, I am here to help you in booking process. Can you please share your travelling dates?

USER: My trip dates are Mar 16 and Mar 18.

ASSISTANT: Do you have any airline preference?

USER: No, I want to depart in the evening.

ASSISTANT: Do you have any class preference?

USER: No, I need a connecting flight.

ASSISTANT: Ok, please wait a moment.

USER: Sure.

ASSISTANT: Sorry, no flights are available on your preferable travel dates.

USER: No problem, thank you.

ASSISTANT: Thank you for reaching us, have a nice day.