They did let you swap a TS for a CS last year and 2006 at the end of sept during
free dining. There was a leaflet in our room both years explaining the swap.
They gave you a coupon at the CS when you told them you wanted to use a TS then you took it to a gift shop and they allowed you to get a disney pin (you dont get to choose my kids swapped them pretty quickly) or a snack.
However I dont know if they will be doing this year nothing is set in stone but as the pp states the ADRs are hard to come by during free dining so maybe they will this year too.