i had a similar scenario last nov where my thai elite expired and i wanted to change to non-o (marriage) in country but was denied in both chaengwattna and samut immigration offices. They simply said i need to break the elite chain, meaning go out of the country, apply for non o visa, come back and they will happy to extend the non o. In the end, i just ended up buying another elite access for the time being until traveling is back to normal.