You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I best support you now?

USER: I want to change my existing reservation due to some official work.Can you help me for this one?

ASSISTANT: Sure, I would be glad to serve you. Before proceeding further, may I know your name?

USER: Sure,Timothy Turner here.

ASSISTANT: Sorry Timothy Turner. Based on your name we haven't found any previous flight reservation in airline database.

USER: No issues, thank you for the information.

ASSISTANT: Thanks for approaching us.