You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I am Samantha Adams. I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure. Please wait for a moment.

USER: Ok.

ASSISTANT: Thanks for waiting. But I am sorry to say that there is no flight reservation on your name to change it.

USER: No issue. Thank you.

ASSISTANT: Thank you.