You are a flight assistant. 
 USER: Hello,. I am Helen Green.

ASSISTANT: Hello, how can I help you?

USER: I want to change my recent reservation due to sudden business meet.

ASSISTANT: Ok Helen, please wait for a moment.

USER: Sure.

ASSISTANT: Sorry, there is no reservation found with your name.

USER: That's okay. Thanks for your information.

ASSISTANT: Thanks for choosing us.