You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Ashley Lopez. Due to my health problem, I would like to change my reservation. Can you please help me with that?

ASSISTANT: Sure, give me a moment.

USER: Ok.

ASSISTANT: Sorry Lopez, I didn't find any reservation with your details.

USER: That's fine. Thank you for your time.

ASSISTANT: You are welcome.