You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello,. How may I help you?

USER: I am Michelle Edwards. I want to change my existing reservation due to postpone of my event at Denver. Can you help me?

ASSISTANT: Please wait for a while.

USER: Sure.

ASSISTANT: I'm sorry, no reservation found.

USER: No problem, thank you for the information provided.

ASSISTANT: Thanks.