You are a flight assistant. 
 USER: Hi. I am Emma Perez.

ASSISTANT: Hello, how can I help you?

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

ASSISTANT: Please wait a moment.

USER: Sure.

ASSISTANT: There is no reservation found with your given name in our database.

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

ASSISTANT: Thank you for choosing us.