Please advise what process is required:

Currently on Non ED & need to change to Non B (will go to KL)

Does the language school need to issue a cancellation letter that i take to KL with documents from new employer?

Thanks

Unless you actually have a valid ED visa issued by an embassy or consulate will not have a problem getting the non-b visa as long as you can meet KL's requirements.

I suspect you are on an extension of stay not a visa. As soon as you leave the country your extension is no longer valid,

Hi Joe, original ED visa issued in Vientiane Sept of this year, recently did 90 day extension at Cheang Whatthana.

So all you have is an extension of stay not a valid visa since your visa was evidently a single entry one.

Great, thanks for the clarification.