You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. I hope you are good, how can I help you?

USER: Because of my friend's marriage postponed, I want to change my existing reservation. Can you please help me in this?

ASSISTANT: Sure, I will help you with that. May I know your name for checking the existing reservation?

USER: Sure, my name is Nicholas Taylor here.

ASSISTANT: I am happy to say that, there is a flight for you. Can you please tell me the travelling details of your journey?

USER: Sure, my travelling airports codes are from ORD to IAH.

ASSISTANT: What were the travelling dates?

USER: My preferable dates are from 06/24 to 06/26.

ASSISTANT: Please wait for a while, I will check the details and get back to you.

USER: Sure.

ASSISTANT: Thank you for waiting Nicholas. There is a flight 1015 in Delta airline has the price 200.Can I proceed?

USER: That's perfect, please proceed with the booking.

ASSISTANT: Your ticket has been booked, have a safe journey.

USER: Thank you for your help in booking.

ASSISTANT: You are welcome.