Yes there are fixes, problem is they divide in to two groups
The yeast failed to ferment all the sugars - probably down to yeast abuse
The yeast did ferment all the fermentable sugars - probably only applies to someone who is all grain brewing and not doing a very good job of it.
Or If the recipe contained lots of Maltodextrin or Lactose it would be possible for a kit brewer to finish that high.
If there are fermentable sugars that the yeast hasn't used, adding more yeast under the right conditions would fix it. Be worth knowing why it failed the first time. A reasonable pitch of healthy yeast should finish fermenting in a week, for the brew to have sat there for two weeks and still not done the job means wrong conditions mostly temperature, not enough yeast, unhealthy yeast (ie badly made starter), poor aeration. A combination of more than one of the preceding.
To test if there are fermentable sugars, about half fill a jar with beer 100-200mL more than enough for an hydrometer reading) , cover and allow to warm to ambient, add a fair amount of dry yeast (1g or so), if its fermenting in a couple of hours - half a day allow to finish and measure new FG.
Doing the same "Fast Ferment Test" will tell you if there are no fermentable sugars, FG wont change. Mainly caused by mashing way too hot or adding too much unfermentable sugars/adjuncts.
In this case about the only option would be to add some dry enzyme. Problem is you might end up going too far the other way and getting too dry.
Which ever way you go, its important to avoid picking up too much oxygen when you transfer back to the fermenter, allow it to warm some, try to arrange a closed transfer to the fermenter, remember the yeast wont be able to reproduce much with low oxygen so use a healthy pitch of a good clean fermenting Ale yeast either with or without Dry Enzyme.
Be well worth having a look at your processes, especially mash temperature, and fermentation temperature.
Also look at you yeast, are you using enough, is it healthy, if you are reculturing or making starters - think through your process as something taint right!.
Mark