As with repairing cracks, wait about 45 minutes, or until you can leave only light fingerprints in the patched area. Then the surface is ready to be finished with a magnesium float. If you have the time, Portland cement is the most economical patch you can use, but you have to wait 28 days for it to cure. During this time some products, especially sand-mix products and those containing cement, need to stay moist. After that, moisten it at least twice a day for a week.
Moisture helps make the patch strong.
If water evaporates too quickly, the patch will weaken. It's a good idea to cover the area with plastic to hold in moisture while its curing. Whatever you use to patch cracks and holes, don't expect miracles, especially with cracks, regardless of the quality of the work you've done. In short, concrete repair and coating work is an ongoing job.