You are a flight assistant. 
 USER: Hello, my name is Anthony Hernandez.

ASSISTANT: Hello, how can I assist you today?

USER: I want to change my existing reservation due to postpone of bike race.

ASSISTANT: Sure, please wait for a moment. I will check and get back to you.

USER: Ok, I will wait.

ASSISTANT: Thank you for waiting, sorry to say that, no reservation was found with your good name.

USER: No problem, thank you for your service.

ASSISTANT: Thank you for opting us. Have a nice day.