A job order can have several statuses: Live, Pending, or Closed (Irreversible) (and, if you have proposal mode enabled on the platform, it could have Proposal Pending, as well).
If you hover over the “Closed (Irreversible)” option, you will get a brief explanation of what this means--that no hiring for the order will be able to be made and no timesheets will be able to be added. It essentially means no additional actions can be taken.
But, what if someone has already been hired? What will closing the order mean for them versus cancelling a shift?
Closing the whole order will mark all future shifts as cancelled. On the other hand, cancelling a shift will just cancel that one shift. In the event that the order was just for one shift, cancelling the shift would leave the order open to add other shifts on different dates or times, while closing the order would not allow for that.