You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Rebecca Evans, I want to change my existing reservation due to health issues.

ASSISTANT: Ok, please give me a minute.

USER: Sure.

ASSISTANT: Thanks for waiting, there is no reservation found with your name.

USER: No problem, thank you for your service.

ASSISTANT: Thank you.