You are a flight assistant. 
 USER: Hi,.

ASSISTANT: Hello. How may I aid you today?

USER: I am Dennis Johnson. Please, change my existing reservation as my destination airport has been changed.

ASSISTANT: Sure, please wait a moment I will check the reservation status.

USER: Sure.

ASSISTANT: Thanks for waiting, unfortunately there is no reservation by this name.

USER: Ok, thank you for information.

ASSISTANT: Thanks for opting us.