You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how may I assist you?

USER: My name is Karen Lopez. I would like to change my reservation, could you help me out?

ASSISTANT: Sure Karen, please give me a moment to check the database.

USER: Sure, take your time.

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

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

ASSISTANT: Most welcome.