I understand that people are curious about this but its been said ad nauseum what this patch actually does. As mentioned the answers are all over these boards.
/sigh
/eyeroll
To the OP... I'll try to be helpful as SOME of us still understand and remember what a community is, and that not everybody is totally forum-savy like ourselves.
Basically what happens is when you reset your Destruction tree down to 15 - it removes and refunds all your perk points.
So, if you have 7 perk points invested in Destruction and knock it back down to 15, your 7 perk points will be refunded back to you.
Why you would want to do this is when you re-build Destruction, you will gain new levels and - subsequently - additional perk points above your refunded 7 that you could put back into destruction or wherever else you like.