You should apply for permanent resident first which is not easy. Then you should live in Thailand for few years, be fluent in thai language, plus money in your account. But first step is applying for permanent resident. But honestly it's very very long story, don't waste your time and money, live on non O visa better
Once your non Visa cancelled dependant visa will be cancelled automatically in the same day. After you get non B your school have to prepare documents for new non O for your BV family. About documents your Hr must know