You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I best serve you now?

USER: I want to change my reservation. Can you help me for that one?

ASSISTANT: Sure, I can change your reservation right now. Before that I need to know your good name please to track the details?

USER: Sure, Justin Nelson here.

ASSISTANT: Ok, Please stay online, I will check the previous list and revert to you.

USER: Sure.

ASSISTANT: Thanks for remaining so positive. We are sorry to specify that, there is no active reservation found on your name.

USER: No issues, thank you for your time.

ASSISTANT: Thanks for choosing us, wish you a great day.