As long as you're changing to your new spouse's name, or returning to your old name, you can usually use the usage method to change your name after you get married or divorced -- you simply start using your new, or old, name. You'll need to provide proof of your name change, but showing your marriage certificate or divorce decree should be enough. However, if you want to change to a new name (for example, you and your new spouse are both taking on a name that's new to both of you, or you want a new name after a divorce) you'll have to get a court order. (For information on changing your name after marriage or divorce, read Nolo's articles Changing Your Name After Marriage or Changing Your Name After Divorce.)