Probably a really dumb question but I figure looking silly in the forum will be a lot less painful than looking silly at the visa counter of the Thai consulate after flying all the way home. Anyway, here goes:

 

I am on an employment visa now which expires Jan. 31, 2018. But my work contract is till Dec. 31 after which I plan to leave for home and return on a non-O, not employment, applying early Jan. So, can I apply the first week of Jan, 3 weeks before my current visa expires, for a non-O? Obviously, this will require my current visa to be cancelled as I guess one can't hold 2 concurrent visas. Is there a chance that consulate will say, hey come back in 3 weeks when your visa expires and we'll look into it, which will totally screw up my travel plans?

There shouldn't be a problem applying before the old visa expires. They will usually cancel the old visa in favour of the new visa being issued.

Thanks, elviajero.