It's a pilot program. The submissions/appeals they are accepting is now closed. Several threads on it are in the forums now. They were only accepting a limited number of accounts for those that were able to fess up, accept responsibility. Riot stated this is only a trial for NA exclusively because they have a greater number of support staff to make it possible.
These players are on the knife's edge. They are even closer to getting repermabanned than someone already on a 14-day suspension. Basically, these accounts are being specifically monitored by specific support group to see if they commit the smallest offense.
The success of the program (demonstrating that permabanned players are able to reform) will dictate whether other regions and future accounts in NA also get the possibility to get unbanned.
I wish all who got in, luck! If ya screw it up, EU will probably never forgive NA lol.