Re: 14 inch flange
There is no adapter that will work without cutting open the floor and replacing the existing flange and pipe. It will be a big job; if the closet bend (the sewer pipe under the toilet) is cast iron or lead, I recommend calling a plumber as it will take special tools and skills that you may not have.
If you can find an old, respected plumber you may have better results. Nobody uses lead pipes anymore, and the methods for fitting cast iron pipes have changed completely since yours were installed. The younger guys may not have the experience to work with it.
The "Senior Member" designation under my name doesn't mean I know a lot, it just means I talk a lot.I've been a DIYer since I was 12 (thanks, Dad!). I have read several books on various home improvement topics. I do not have any current code books I can refer to. I was an apprentice plumber for two years.