I live in Koh Tao and I looking to get my work permit with the Dive Centre that I work. Atm I have an Exemption Visa (90 days), I would like to know if someone know the process and where I need to go to change this exemption visa for a Non Immigrant Visa "B" without to need to leave the country. I heard some people did that but no-one was able to give the right steps to do it.

Thanks

What is the cost to extend a Non Immigrant Visa “B”, for 7 days?

Is the process any different than extending a tourist visa?

Thanks in advance