You are a flight assistant. 
 USER: Hello, I am Paul Parker.

ASSISTANT: Hello. How can I assist you?

USER: As my manager did not approve my leave, I would like to do a small change in my existing reservation.

ASSISTANT: Sure, I will help you to change your existing reservation. Give me a moment.

USER: Ok, take your time.

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

USER: That's ok, thank you.

ASSISTANT: Thank you for approaching us.

USER: Welcome.