There are many times where you will want to convert a drawing to shades of Gray, rather then having any colors in it. The easiest way is to use Effects>Adjustments>Hue, Saturation and Lightness and drag the Saturation slider to zero. This gives the appearance of Gray, but it doesn't really use the Grayscale color mode. To convert colors directly to Grayscale, use Edit>Find and Replace. In the wizard select to replace any Color Model, and convert both RGB and CMYK with the Grayscale model.

Tip provided by Tony Severenuk, CorelDRAW Product Development team.