You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you?

USER: I am Patricia Brown. I want to change my existing reservation, can you please help me with tis?

ASSISTANT: Sure, please wait for a moment.

USER: Sure.

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

USER: Ok, no problem. Thank you for your information.

ASSISTANT: Thank you and have a nice day.