You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I help you?

USER: Can you book a flight ticket from SFO to LAS?

ASSISTANT: May I know your travelling dates please?

USER: I will start on Apr, 18 and return on Apr, 20.

ASSISTANT: Do you have any connection limit?

USER: I would prefer to connecting flight.

ASSISTANT: Do you have any other specifications?

USER: I would prefer to fly with major airlines.

ASSISTANT: There is a flight with single connection in American airlines, can I proceed for booking in economy class?

USER: Please proceed.

ASSISTANT: On which name can I proceed for booking?

USER: William Evans here.

ASSISTANT: Your booking is done in 1001 flight.

USER: Thank you.

ASSISTANT: Thank you for choosing us.