Can I change my visa status from student (ED) to business in Thailand?

You cannot change from education to work.

If you're on the initial 90 day visa, you could just leave Thailand without a re-entry permit and apply for a non-B at a Thai embassy nearby. Or if you can receive visa exempt just return without a visa and apply to convert at immigration (if your company can support an in county conversation, many cannot or will not).

If you're on an extension (the stamp in your passport says extension of stay) then you'll need to get a letter from your school stating when you'll finish studying. Take that letter to the immigration office that issued your extension and have it cancelled. Then you can follow the instructions above.

If you have an extension and don't cancel it first, you won't be able to get another long term visa or extension in Thailand until you do, and will be subject to a 500 baht per day fine for failing to cancel it.