Use Erase 
to erase stitches of the selected type. It can then be used to erase stitches when a stitch drawing function is selected. When a cross type is selected, it erases crosses according to the size of the selected cross type. To erase Standard Backstitch, Freehand Backstitch or French Knots, the corresponding draw function must be selected. Erase also works with Cross Flood Fill 
to erase an area of connected crosses of the same color.
To Erase stitches
-
Select Erase
in the Create window 
, then select the stitch type to erase (crosses, backstitch or knots). Click or drag on the work area to remove stitches. -
Select the stitch type to be erased (crosses, backstitch or knots). Press the Option key, then click or drag on the work area to remove stitches.