You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you?

USER: I want to change my existing reservation. Can you help me?

ASSISTANT: Sure, We are here to assist you.

USER: Thank you.

ASSISTANT: May I know your name?

USER: Yes, I am Barbara Anderson.

ASSISTANT: Give me a  minute.

USER: Sure.

ASSISTANT: We found a reservation by this name. Can I know your updates travelling dates?

USER: Ok, my planned trip dates are on Apr 30 and return on May 02.

ASSISTANT: May I know your airport codes?

USER: Yes, my airport codes are from ORD to LAS.

ASSISTANT: Do you have any connection limit?

USER: No, I don't have any connection limit.

ASSISTANT: There is a flight with your requirement, airline is United Airlines with price 300 and single connection. Shall I proceed with booking?

USER: Ok, you can proceed with the ticket booking.

ASSISTANT: Your booking is done and flight number is 1012.

USER: Thank you for your help.

ASSISTANT: Thanks for reaching us.