Can I extend my Non-Immigrant O visa with a work permit under BOI after my company's closure?

@Sanjeev *************

you take your termination paperwork to the Cham Churi Square BOI immigration office (if you're in bangkok) you cancel the extension and they will give you between 7 and 21 days from that date to get out of thailand.

That's how that works with BOI/IEAT companies.

There is no wiggle room, there is no "automatic cancellation"

YOU take the passport to the immigration office that issued the extension and cancel it.

THEN you figure out if there's any other extension you could apply for; married to a thai or thai children visit family extension for 60 days, etc.