You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I serve you the best today?

USER: I am Andrew White, can you please help me to change my travelling of previous reservation?

ASSISTANT: Sure, we are here to help you.

USER: Thank you.

ASSISTANT: Please give me a moment.

USER: Sure.

ASSISTANT: Thanks for giving your valuable time for us. We are regret to inform you that, there is no active reservation found in your name.

USER: Ok, not a problem. Thank you.

ASSISTANT: Thank you for choosing us, we will try to serve you for the next time.