You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I  help you?

USER: I need to change my existing reservation due to postpone of my event which was conducted by my friends. Could you please help me?

ASSISTANT: Sure, may I know your name please?

USER: I am Charles Martin.

ASSISTANT: I am sorry no reservation found on your name.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for choosing us.