You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you now?

USER: I need to change my reservation due to planned event got postponed. So please help me with that.

ASSISTANT: Ok, may I know your name to check the reservation records?

USER: Sure, myself Karen Roberts.

ASSISTANT: Sorry, there is no reservation found on your name.

USER: It's ok, no problem. Anyway, thank you for your time.

ASSISTANT: Thank you for aviling our agency.