You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: I want to change my existing reservation due to postpone of my event. Could you please help me?

ASSISTANT: Sure, I am here to help you. In whose name, I want to check the reservation?

USER: I am Donna King.

ASSISTANT: Ok, please allow me a few minutes.

USER: Sure.

ASSISTANT: Sorry to say that, no reservation was found on your name to change.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for choosing us.