You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I help you?

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

ASSISTANT: May I know your name to proceed further?

USER: I am Margaret Harris.

ASSISTANT: Please wait.

USER: Sure.

ASSISTANT: No reservation found as per preferences at the moment.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for choosing us.