You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

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

ASSISTANT: Sure, may I know your name?

USER: My name is Benjamin Nelson.

ASSISTANT: Sorry, there is no active reservation on our name.

USER: No problem, thank you.

ASSISTANT: Thank you.