The below photos show a transformation of the POPS at West 57th St from a pretty much useless plaza into an urban park including a childrens play area.
The article I found these images on said "The community pressured for change". Beyond the community pressure it may have also been part of a deal that rather then the 24 hours a day that the plaza was required to be openm t he new park is allowed to close at night. This gives leverage to transform POPS plazas into parks.
see also: Flatiron Plaza Active and Community Recreation Area Proposal