The Change Route Diameter command now uses the PropertyManager instead of a series of dialog boxes. The route elements that are being changed highlight in the graphics area.
and Routing Tools
(Route toolbar).
(Piping toolbar) or Routing, Piping, Edit Existing Piping Route.
(Routing Tools toolbar) or Routing, Routing Tools, Change Route Diameter.The first section of the route, including the flange and tee, changes color, indicating that this section of the route corresponds to the items in the PropertyManager. Because you selected near the flange, the flange appears under First Fitting in the PropertyManager.

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The next section of the route highlights.

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The elements of the route change.

See Change Route Diameter in the help.