You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how can I aid you?

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

ASSISTANT: Sure, may I know your name?

USER: Debra Anderson here.

ASSISTANT: Give me a minute for checking.

USER: Sure.

ASSISTANT: Sorry, we did not found any reservation under your name.

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

ASSISTANT: Thank you for choosing us.