You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: This is Barbara Carter.

ASSISTANT: Yes, tell me.

USER: I need a flight ticket from CA-SFO to IL-ORD,can you book this flight ticket?

ASSISTANT: Yes definitely. Please give me your trip dates.

USER: My departure day is 04/21 and arrival day is 04/23.

ASSISTANT: In Delta airline, price is 100 with 1 connecting flight. Would you like to choose this flight?

USER: Yes please book this ticket.

ASSISTANT: Ok. Your flight ticket is booked.

USER: Thank you for your help.

ASSISTANT: Welcome.