Should be possible with Tourist Visa as long as you have enough time left and you actually fill the requirements of the visa you are wanting to change to.
You seem to be confused as to what visa you have. There is no Non-O with a validity of 180 days.
You likely have a multi entry tourist visa.
Figure that part out first.
With the multi entry tourist visa, you should be able to enter just before it expires in December, and be stamped in for 60 days, which you can extend with another 30 days.