You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: My name is Michelle Gonzalez.

ASSISTANT: Yes.

USER: Could you please help me to change my existing reservation?

ASSISTANT: Sure, please give me some time.

USER: Sure.

ASSISTANT: Sorry, no reservation found by your name.

USER: That's ok. Thank you for the information.

ASSISTANT: Thank you and have a nice day.