Depends on just how bad the default is but they'd likely go into some kind of managed bankruptcy. Since WeWork doesn't actually own the buildings companies could wind up making deals more directly with the CEO who does own the buildings to at least maintain the space so they'd just lose the other services provided by WeWork and wind up in a more normal relationship with the building owner. Hard to know without it happening because it depends so much on the details of how it happens and the reaction of so many parties.