Using the Markup Polygon Tool Acrobat 9 Pro

If you click an existing polygon once with the object select tool (blue arrow), handles appear on each vertex and you can just drag one across to mirror the triangle. There's no tool to rotate the comment as a whole.

I must be doing something wrong. When I grab the box at one vertex of the polygon with the Select Object tool and drag it, the entire polygon simply moves in the direction of the drag. Do I need to hold down some key while dragging?

Use the "Select Tool" (the I-beam + arrow) that, typically, is next to the Hand Tool.

Open the Edit Toolbar. With the "Select Tool" in use, click on a triangle.
On the Edit Toolbar, click the "Copy" feature. Paste new triangle - it'll be in center of page.
Position new triangle. Helps to have the grid showing (Ctrl+U, Cmd+U).
"Select tool" to a square on desire vertex.
Click-drag to re-shape the triangle into a mirror of the first.

Fun -- thank you rauckr & UVSAR! Playing with Acrobat bets Jewel Quest .Be well...

Thank you very much. I was confusing the Select Tool with the Select Object Tool. Your explanation cleared it up and I was able to effectively mirror a triangle. I am surprised that Acrobat does not have a more powerful set of tools for flipping and rotating objects.

The TouchUp Objects Tool contains all the features I seek. Unfortunately, it does not operate on objects created by the Comment & Markup Toolbar. This seems like a significant missing capability.