Effects > Warper > Modifying a Mesh > 
Moving Control Points, Edges, and Tangent Handles
 
 
 

You can manipulate control points and tangent handles on the mesh to add precision to your warp effect. Click the control points to access their tangent handles, then click the tangent handles to change the shape of a patch.

Click the Move button to move a vertex, an edge, or a tangent handle.

To: Click:
Move a control point The control point and drag.

Note that the X, Y, and Z coordinates of the selected vertex appear in the corresponding fields in the menu.

Move an edge Near the centre of the edge and drag.
Move a tangent handle The corresponding vertex to display its tangents, then click the tangent handle and drag.