I accidently warmed up Fleishig Soup in a covered Milchig Soup Plate made of Corelle (Corning Ware)in my microwave. Afterwards, I mixed the soup with a steel milchig fork. Can I kasher the corelle soup bowl? What else do I have to do?

There are very many different opinions about the status of Corelle - is it a glass - or like Parcelean Hereo. You may Kasher the plate in boiling water and the milchig fork too. My opinion is not to be considered as good for any situation concerning Corelle.