You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: My name is William Roberts.

ASSISTANT: How may I help you?

USER: I want to visit Atlanta to visit my friend, could you help me in booking the ticket?

ASSISTANT: Sure, may I know your airport codes?

USER: It's from DCA to ATL.

ASSISTANT: Ok, could you tell me the dates of journey?

USER: The dates of travel are from 09/13 to 09/15.

ASSISTANT: I found a flight for you with 1009 in JetBlue airline.

USER: Please book the ticket.

ASSISTANT: Ok, your ticket has been booked.

USER: Thank you for helping me out.

ASSISTANT: Thank you for choosing us.Have a nice day.