You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

USER: I have planned to book a plane ticket from DCA to OAK, can you assist me?

ASSISTANT: Sure, please share your journey dates?

USER: My preferred dates are Mar 21st and Mar 23rd.

ASSISTANT: Do you have any specifications?

USER: I need single connection between my trip.

ASSISTANT: Is there any class preference?

USER: I need to travel in economy class.

ASSISTANT: May I know your good name?

USER: Amy Hernandez.

ASSISTANT: Sorry, no flights found on your given details.

USER: No problem, thank you for searching.

ASSISTANT: Thank you for choosing us.