You can modify your sketched shapes on-the-fly using the Smart Drawing Tool to backtrack and erase the paths you are drawing. Hold down the SHIFT-key as a modifier to reverse and erase a path. Release the SHIFT-key to resume sketching normally. (Note: in CorelDRAW X7 the Smart Drawing tool is included in the Default workspace and can now be found under the Drawing tools fly-out panel).

Tip provided by Silvio Gomes, CorelDRAW Master, Artist and Graphic Designer.