You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello.

USER: Dennis William here.

ASSISTANT: How may I assist you?

USER: I would like to change my reservation, can you please help me out with that?

ASSISTANT: Sure, I will help you.

USER: Thank you.

ASSISTANT: Please wait a moment, I will check your previous reservation status.

USER: Sure.

ASSISTANT: Dennis, no reservation has been found on your name in our database.

USER: That's ok, no problem. Thank you for the information.

ASSISTANT: Thank you for reaching us.