After publishing a schedule, certain functions and buttons are no longer visible (Import, AutoFill, Clear/Delete). It is assumed that you will be making only minor changes to the schedule after you publish it. Before you publish, be sure that you have completed the scheduling as much as possible for that week.
You can always make changes to shifts on Published schedules by clicking the shift on any weekly schedule view or by using the Multi-Shift Edit view to change a number of shifts at once.
If you have several changes to make to an already published schedule, you may want to Unpublish the week, make the changes and then Publish it again. Please see UnPublishing for important information on this topic.