You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello. How may I assist you?

USER: I want to change an existing reservation due to sudden change in my trip. Can you help me?

ASSISTANT: Sure, I am here to help you out.

USER: Thank you.

ASSISTANT: May I know your name please?

USER: I am Benjamin Taylor.

ASSISTANT: Wait a moment please.

USER: Ok.

ASSISTANT: Benjamin Taylor, we haven't found any reservation under your name in our database.

USER: No issue. Thank you.

ASSISTANT: Thank you for choosing us.