You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you?

USER: Can you please help me in changing my existing reservation?

ASSISTANT: Yes, I am here to help you.

USER: Thank you.

ASSISTANT: May I know on which name the ticket has been reserved?

USER: I have previously reserved the ticket with my name Nancy Campbell.

ASSISTANT: Ok, please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, we found a reservation on your name. Can you please share your travelling dates?

USER: My preferable journey dates are Jan 21 and Jan 23.

ASSISTANT: Ok, may I know your airport codes please?

USER: My airport codes of journey are from SEA to ORD.

ASSISTANT: Do you have any other preferences?

USER: No, I don't have any specifications for this trip.

ASSISTANT: Please wait a minute.

USER: Sure.

ASSISTANT: Thank you for waiting, we found a flight with number 1000 at a price of 200 and it is a direct flight in economy class which is provided by Delta airline. Shall I proceed?

USER: Please book my ticket in this flight.

ASSISTANT: Sure, your ticket is booked.

USER: Thank you for booking my ticket.

ASSISTANT: Thank you for reaching us, have a good day.