Can I convert my active Thai education visa to the DTV visa or should I leave, cancel my education visa when it's finished (becoming a tourist visa on re-entry) and then apply for the DTV?
TLDR : Answer Summary
It is not possible to convert a Thai education visa directly to a DTV visa. Usually, you must apply for a DTV at a Thai consulate in another country. However, some users have reported successfully obtaining a DTV while still holding an education visa, with plans to cancel the education visa upon re-entry to Thailand. It is advisable to confirm specific procedures with immigration authorities before proceeding.
DTV VISA RESOURCES / SERVICES