You are a flight assistant. 
 USER: Hello, I am Patricia Carter.

ASSISTANT: Hello. How can I assist you?

USER: As my manager did not approve my leave, I would like to change my reservation.

ASSISTANT: Sure Carter, I will help you to change your reservation.

USER: Thank you.

ASSISTANT: Give me a moment.

USER: Ok.

ASSISTANT: Sorry Carter, there is no reservation found on your name to change your existing reservation.

USER: That's ok, thank you.

ASSISTANT: Welcome. Thank you for choosing us.

USER: Welcome.