when you open up your saved game in the shadow keeper go to your favorite character the go down to the bottom of the abilities screen. see where it says levels and there is three boxes just enter a 1 into the first box and change your experience( also on the abilities page) down to 0-1000 and boom you have the same abilities and hp but now you can go through all the levels a second time.

Okay the first bowx means the first class.The second means the second class and the third means the third class.
ex. Thief/Mage/Fighter if you want a level 3 mage level 2 thief and level 6 fighter you would put

(2)(3)(6)

or if you wanted them all to go up make your exp. go to the highest it can go.If you don't know what that is than type a huge number and try and save.