You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello.

USER: I am Amanda Green.

ASSISTANT: Please let me know, How can I serve you the best today?

USER: I want to change my existing reservation, please help me out.

ASSISTANT: Sure, I can help you in that.

USER: Thank you.

ASSISTANT: Please wait for a while.

USER: Ok.

ASSISTANT: Sorry Amanda Green, there is no active reservation on your name to change it.

USER: No issues, thanks for the response.

ASSISTANT: Thanks for approaching us.