You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I help you?

USER: I want to change my existing reservation due to some health issues, can you please help me in this intent?

ASSISTANT: Sure may I know your name to proceed?

USER: Sure, my name is Eric Lopez here.

ASSISTANT: Please give me a moment to check Eric.

USER: Sure, take your own time.

ASSISTANT: Sorry Eric, there is no reservation found on your name.

USER: No problem. Thank you for your service.

ASSISTANT: You are welcome.