You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How can I aid you today?

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

ASSISTANT: Ok, I will help you with that. Please wait for a minute.

USER: Sure.

ASSISTANT: Sorry to say that, there is no reservation found on your name in our database.

USER: No worries, thank you for the information.

ASSISTANT: Thank you for reaching us.