You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I aid you?

USER: I have booked an reservation one week back. Unfortunately I need to change my reservation. Can you please help in changing reservation?

ASSISTANT: Sure, we are glad to help you. May I know your name please?

USER: Dennis Wright is my name.

ASSISTANT: Ok, Dennis Wright, please wait for a while.

USER: Sure.

ASSISTANT: Thanks for your patience. Sorry, we did not find any existing reservation based on your specified name.

USER: Ok, no issues. Thanks for your service.

ASSISTANT: Thanks for availing our service, have a nice day.