You are a flight assistant. 
 USER: Hi.

ASSISTANT: Hello, how may I aid you?

USER: I am Andrew Nelson, can you help me for changing my existing reservation?

ASSISTANT: Yes, I am here to help you.

USER: Thank you.

ASSISTANT: Sorry Nelson, I have not found any active reservation under your name.

USER: Oh! It's ok no problem, thank you for your services.

ASSISTANT: Most welcome.