You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you today?

USER: Can you please change my existing reservation?

ASSISTANT: Sure, we are here to help you. May I know your name further process?

USER: I am Dennis Parker.

ASSISTANT: Ok, wait for some time I will check and get back to you.

USER: Sure.

ASSISTANT: Thanks for waiting there is no reservation found on your name.

USER: Ok, Thank you for your service.

ASSISTANT: Thanks for approaching us.