You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: Can you assist me to change my existing reservation as my exams got postponed?

ASSISTANT: Sure, may I know your name please?

USER: I am Scott Lee.

ASSISTANT: We found a reservation with your given name, please share your new journey dates.

USER: My journey dates are Mar 20 and Mar 22.

ASSISTANT: May I know your source and destination airport codes?

USER: My airport codes are from IAD to LAX.

ASSISTANT: Do you want connecting flight or direct flight?

USER: Yes, I require a connecting flight.

ASSISTANT: Do you have any airline preference?

USER: I am comfortable with any airline.

ASSISTANT: Do you have any class preference?

USER: No, thank you for asking.

ASSISTANT: May I know your depart time and return time?

USER: I do not have any particular timings.

ASSISTANT: Ok, we found an UA airline, flight number: 1014, price: 100 with one connection.

USER: Ok, proceed for booking.

ASSISTANT: Your flight ticket has been confirmed in economy class.

USER: Thank you for booking.

ASSISTANT: Thank you for choosing us.