Donald Draper wrote:
There is a lot of overlap between Retcon and Reboot. A lot of times there is not much difference.
"Retcon" means "retroactive continuity", which happens when you insert facts and character retroactively in the franchise's past as if they had always been there. A reboot means that you completely erase all continuity and start again with a new one. I don't think there's a lot of overlap between those two concepts.