Deinstallation
The physical act of taking an artwork down, including rigging, transport, and making the site safe, as distinct from the decision to remove it.
Deinstallation is the highest-risk moment in most works' lives. More damage happens during handling, lifting, and transport than during years of weather on site, and outdoor works are especially vulnerable because they were engineered to sit still rather than to be moved. A condition report before the work comes down and another after it lands gives everyone an honest record of what the move cost.
The other discipline is photographic. Once a work is off its base, the relationship between the piece and its site exists only in pictures, so the last hour before deinstallation is worth more documentation than the whole year preceding it: the work in context, the sightlines, the footings, the signage, and any damage already present. Crews are focused on the object, which is why somebody should be assigned to the site.