The -D is attached so that brokerage houses are aware of the change. Most put a temporary "chill" on until they have their numbers adjusted. Once they are done, they will allow you to trade under the -D, which will stay on for 20 days. 

I use Scottrade, and last time I underwent an R/S (about a month ago), I was on "hold" for about  a week or so, and then I was back to trading. Every brokerage has a different time frame.

Best.