You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I help you?

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

ASSISTANT: Sure, we are here to help you. May I know your name please?

USER: My name is Emma Smith.

ASSISTANT: Sorry to inform you that there is no active reservation on your given name.

USER: Not an issue, thank you.

ASSISTANT: Thanks for contacting us.