I'm about to leave Thailand for change my Non-B to Non-O but i wonder if i leave the country, My non-b visa and work permit will cancel right away? or i hvae to cancel it first at the immigration before leaving the country? 

 

Pls,advise 

Why are you wanting to change to a non-o?

Your work permit needs to be canceled. If you are on an extension of stay (it is not a visa) you should also cancel it.

If you are leaving at a border crossing there have been reports of immigration turning people back if they still have a valid extension of stay.

Non B sticker is single entry (or mine have been), so that'll cancel itself if you leave. The yearly extension stamp won't automatically cancel in the system, and you'll be able to travel on that until you've notified them, which you're obliged to do straight away. The work permit book is supposed to be returned to the relevant dept.