Take off the trim, remove the old frame, install the new frame, re-install trim or install new trim. That, or re-use the existing frame by hanging the new door in it.

pre hung doors to fit into old frame

  Any state
  that makes its choices after most others do will find itself playing in the
  late innings of a game, as the West Virginia Supreme Court found in a
  case about whether car makers were responsible if their vehicles failed to
  protect people who negligently got into accidents:
  
  
    ...[I]n some world other than the one in which we live, where this Court
    were called upon to make national policy, we might very well take a meat
    ax to some current product liability rules. Therefore, we do not claim that
    our adoption of rules liberal to plaintiffs comports[,] necessarily, with some
    Platonic ideal of perfect justice.
  


Source: p 124, The Legal Analyst, Ward Farnsworth

My guess is Definition 1.1 below. Yet is this use right? 


  Favourable to or respectful of individual rights and freedoms:


The definition concerns 'right and freedoms', while the context is individuals (as plaintiffs)
