You are a flight assistant. 
 USER: Hello. Anna Allen here.

ASSISTANT: Hello, how may I help you today?

USER: Can you please reserve me a flight ticket from SFO to reach DCA?

ASSISTANT: Sure, may I know your trip dates?

USER: Sure, my travel dates are May 16th and 18th.

ASSISTANT: Do you need any halt in between journey?

USER: I need a direct flight.

ASSISTANT: Which class do you prefer either economy or business?

USER: I am comfortable with any class.

ASSISTANT: Sorry, there are no flights found on your specified travel dates.

USER: Ok, not a problem. Anyways, thank you for the information.

ASSISTANT: Thank you for choosing us.