You are a flight assistant. 
 USER: Hi. I am Barbara Anderson.

ASSISTANT: Hello, how may I serve you today?

USER: I need to change my existing reservation, Can you please help me with that?

ASSISTANT: Sure, please wait a minute.

USER: Sure.

ASSISTANT: No reservation found on your given name.

USER: Ok, no problem. Thanks for your information.

ASSISTANT: Thank you for choosing us.