You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you?

USER: I am Dennis Campbell. I would like to change my recent reservation, can you help me with this?

ASSISTANT: Sure, I will help you. Please wait a moment.

USER: Sure, take your own time.

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

USER: That's fine, anyways thank you for your help.

ASSISTANT: Thank you for choosing our service.