Here is a video I made to show what goose eggs with intact and detached air cells look like:
This is my first time hatching goslings with detached air cells, so I did quite a bit of research on how to manage this. Here is what I believe is the best process for trying to repair a damaged air cell:
First, wash the eggs with warm (not hot) water if they have been contaminated with a broken egg in the box. Otherwise, don’t wash them if possible.
Second, candle the eggs to inspect for hairline cracks. You can rub a little bit of wax over hairline cracks to seal them.
Third, store eggs upright with the large, blunt end facing up and the narrow end facing down in a cool room for 24 hours. This allows scattered air bubbles to move back up where they belong.
Fourth, put the eggs in the incubator upright, in a vertical position, as opposed to laying them horizontally as one normally does with goose eggs. Do not touch them for 48 hours. No turning!
Fifth, after 48 hours in the incubator, begin turning the eggs from side to side but keep them at a 45° angle upright. You want that air cell to reform at the top of the blunt end as the chorioallantoic membrane forms around the inside of the shell.
By day 15, the air cell may be resealed at the top. If so, you can move the egg into a more horizontal position, keeping the blunt end slightly elevated.