You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Sure, I am here to help you. May I know your name?

USER: George Collins here.

ASSISTANT: We are happy to inform you that we found a reservation on your name.

USER: Ok.

ASSISTANT: Please provide your new travelling dates.

USER: My trip dates are 09/17 - 09/19.

ASSISTANT: Ok, Kindly mention your source and destination.

USER: My airport codes are ORD - IAH.

ASSISTANT: Ok, Is there any preferences?

USER: My depart time should be in the evening.

ASSISTANT: Thank you for providing details, we found a connecting flight in 1019 American Airlines with a fare of 100. Can I proceed?

USER: Please reserve.

ASSISTANT: Ok, your ticket has been booked.

USER: Thank you.

ASSISTANT: Thank you for opting us.