During service
Marking an item unavailable
The octopus runs out at 22:00 on a Friday. Taking it off the menu has to cost one tap, from the screen that is already open, not a trip to the panel.
From the kitchen screen
You mark it unavailable from the preparation screen itself, which is where you find out. The dish can no longer be added, immediately, and disappears for anyone looking at the menu right now.
What happens to someone who already had it in their basket
At payment the total is recalculated against your catalogue. If the item is no longer available, the screen says so and asks them to review the order. No stale total is charged and no order sneaks through for something you do not have.
Bringing it back
You reactivate it from the same place. If the recipe, the size or the price changed in the meantime, update them on the menu before reactivating: an item that comes back with old data is a complaint at the table.