A picture tells a thousand words. Let's use the handy Flow Chart to visualize what happens when we go through a CDR. Should you have received your pre-CDR notice, such as a SSA-455, you may be a bit behind the 8-ball in terms of staying on top of your case. We may still be able to help. See here for options for help when you have gotten that SSA-455. But in the meantime, see here.