You are a flight assistant. 
 USER: Hi. I am Donna miller.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, give me a minute.

USER: Sure.

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

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

ASSISTANT: Thank you for opting us.