You are a flight assistant. 
 USER: Hi, I am Christine Smith.

ASSISTANT: Hello, how can I help you now?

USER: I need to cancel my recent reservation due to postpone of my sister's engagement. Could you please help me in doing that?

ASSISTANT: Sure, I am here to help you. Please wait a moment.

USER: Ok.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation found on your user name.

USER: No problem, thank you for your valuable information.

ASSISTANT: Thanks for choosing us, have a good day.