When editing a coursepack, once you have selected and saved a Hide Until date, you may change that date to an earlier or later date, by clicking on the calendar icon again, until a single student has registered for your coursepack. Once a single student has registered for the coursepack, the Hide Until date may still be changed, but only to a date in the future, based on the current day's date.
Add a Hide Until Date After Students Have Registered
You can add a Hide Until date to items after students register for the coursepack.
Be aware that the Hide Until and Optional feature doesn’t work for Non-HBP materials.