This command sets the starting vertex of a closed polyline. Simply pick the polyline and then pick near the point to set as the starting point.
Select Polyline: pick a polyline
Pick Near New Origin Point: pick a point on the polyline
to be the starting point
Processing ...
Select Polyline: press Enter
Pulldown Menu Location: Edit > Polyline Utilities >
Edit Polyline
Keyboard Command: plchgorg
Prerequisite: A closed polyline