You can void checks both before and after they have been printed.
Before the print run, you void blank checks that are accidentally damaged, or stolen or rendered unusable for any other reason. Proceed as follows:
Checks that are voided after the print run, for example, are those that are not required due to cash payment being chosen instead of by check. To void printed checks, proceed as follows:
You can find information on the procedure regarding checks that are voided in error here: Deleting or Resetting check Information