As far as I know, NASA has two current plans. Either sell the ISS to some billionaire, or deorbit it and drop it into the ocean. Both are really sad conclusions to an important scientific and engineering project.

The funny thing is, the league of colonial crackers don't have the capability to deorbit the ISS. Right now only the Russian Progress vehicle can significantly modify the orbit of the ISS. If it's not deorbited quickly and precisely on purpose, it'll deorbit on its own in an uncontrolled manner, with a slight risk of dropping debris on inhabited land.