Open the employee's timesheet detail page, click Edit on the timecard row and then Delete Timecard at the bottom of the window. The timecard is removed and the row reverts to No-Show if a scheduled shift still exists for that slot; if there's no linked shift, the row disappears entirely. Any breaks that were logged on that timecard are no longer shown anywhere once it's deleted. This requires the Edit Employees Timesheets permission (and the Human Resources module). Deleting the timecard is also the required first step before you can remove a shift the employee had already clocked in to — Sprwt blocks deleting a shift with the message "You cannot delete this shift since the employee already Clocked-in."