You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello. How may I assist you today?

USER: My name is Dennis Allen and I would like to change my reservation.

ASSISTANT: Sure, we are here to help you. Please wait a minute.

USER: Sure, take your time.

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

USER: No problem, thank you for the help.

ASSISTANT: Thank you for availing us.