The Same Day command informs the schedule that the operation must start and end on the same day.  The command is selected in the Option section of the Mfg Order Job Details Operations Grid.

If both Same Day and Same Shift commands are selected, Same Shift takes precedence over Same Day.  If either of these commands are selected, it is your responsibility to make sure that the operation time specified will fit within the timeframe of the same day or the timeframe of the same shift depending on the command used.  If the operation does not fit within the timeframe specified, the scheduler will print a warning message to the schedule status report and the job will not be scheduled.