You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I assist you today?

USER: I am Barbara Perez, want to alter my existing reservation due to some personal issue. Please help me out with that.

ASSISTANT: Sure, please wait for a moment.

USER: Ok.

ASSISTANT: Sorry, there was no reservation found with your given name.

USER: It's ok, thank you for your help.

ASSISTANT: Thank you for opting us.