Can I cancel DTV to exchange to work permit THL?
TLDR : Answer Summary
Yes, you can cancel your DTV (tourist visa) to exchange it for a work permit in Thailand. To do this, you need to be offered a job by an employer in Thailand who will then apply for the necessary work permit. Your employer will get a WP3 pre-approval letter from the Ministry of Labour, which you will need to accompany your application for a Non-B visa. It's important to have your DTV cancelled first before applying for the Non-B visa.
DTV VISA RESOURCES / SERVICES