Yes, you can, however, it’s a long process that is probably not worth the effort.  If you want to try this, let the scape produce a flower. Let the flower dry on the plant and then harvest it. Loosen the little bulbils. Plant in the fall. In the following summer, you should be able to harvest a one-clove garlic “bulb” from each plant. You’ll then replant that clove in the fall to produce a whole head of garlic the following year (in the summer).  It’s a long process that most people don’t bother with.  If you want to be self-sufficient when it comes to garlic, just plant more cloves than you need and keep some of your garlic bulbs as planting stock to plant in the fall.