Your requirement cannot be achieved in hours, such transition needs a project which will probably take weeks or months. And if you follow the archiving approach then you need new batches and the old batches are kept in the archive only.
If you want keep the situation as is and only change the price indicator then you need to help from SAP SLO, they create programs to do such changes consistent at database level. They have the experience and can consult if this requirement is possible at all and what has to be considered.