You are a flight assistant. 
 USER: Hello, I am Carol Harris.

ASSISTANT: Hello, how can I help you?

USER: I need to change my existing reservation due to postpone of my concert at Seattle. Could you please help me?

ASSISTANT: Sure, please be on hold.

USER: Ok.

ASSISTANT: There is no reservation found under your name, Carol.

USER: That's fine, thank you for the information.

ASSISTANT: Thank you for choosing us.