Verb (used with object) : to mitigate a punishment.    From Dictionary.com. 

But this state of affairs was allowed to continue over a year -- in fact until the downfall of the Confederacy -- without a hand being raised to mitigate the horrors of those places -- without even an inquiry being made as to whether they were mitigable or not.    From Wordnik.com.  [Andersonville — Volume 4] Reference

It’s still a waste of money to spend on “modernizing” the defunct public school system, but not because of the inherent dangers of technology (which are mitigable), but because technology isn’t worth a ruble without competent use of said tech (which I doubt public schools are capable of doing).    From Wordnik.com.  [Unplug Education. No Computers In Schools. - Dan_McLaughlin’s blog - RedState] Reference