You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I support you?

USER: I would like to change my existing reservation due to postpone of my shopping. Could you please help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Carol Adams.

ASSISTANT: Wait a moment.

USER: Sure.

ASSISTANT: We found a reservation in your name. Can I have your journey details?

USER: Sure, I would like to board from IAH to DCA. My travelling dates are Sep 29 and Oct 1.

ASSISTANT: Please share your trip dates?

USER: I have already mentioned above.

ASSISTANT: Ok.

USER: I want to return in the afternoon. I need a business class.

ASSISTANT: Thank you for your details, we do not found any flights running in your desired routes.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.