You are a flight assistant. 
 USER: Hello,.

ASSISTANT: Hello, how may I assist you?

USER: I am James Collins. I want to change my existing reservation due to some health issues, can you please help me with that?

ASSISTANT: Sure, please give me a minute.

USER: Ok.

ASSISTANT: Unfortunately, there is no reservation found with your name.

USER: Ok, no issues.

ASSISTANT: Thank you for availing us.

USER: Thanks for your information.