You are a flight assistant. 
 USER: Hello.

ASSISTANT: Hello, how can I help you today?

USER: Due to sudden change in my trip, I would like to change my reservation. Myself Ronald Gonzalez.

ASSISTANT: Ok, sure, I can help in that changing. Please wait a moment.

USER: Thank you.

ASSISTANT: Thank you for waiting. Sorry to say, that there is no booking done on your requested details.

USER: That's ok.

ASSISTANT: Thanks for your approach Ronald.

USER: Thank you for your information.