If you haven't been in touch with someone for a long time, it's possible that your friend has changed her name. This is especially true for women, who often take their husband's name after marriage. To find proof of a name change, take a look through your state's marriage records and court records. You can then search all the names you've located using an online people search directory.

If the person you're looking for changed her name after marriage, it's a good idea to locate a copy of her marriage certificate. It will be much easier to find your friend if you know what her married name is. Visit the website of the National Center for Health Statistics, and click on the state where the person you're looking for lives. Read the section in the "Marriage" tab. This either tells you where to write to get a copy of the marriage certificate or links to a page with information for that state. You can usually search marriage records using only the woman's maiden name.

If the person has changed his name in circumstances other than marriage or divorce, then he might have obtained a court order. Members of the public can usually access court records unless the file has been sealed. Start by browsing the official state links maintained by the National Center for State Courts, which link to case and docket information in the area you're searching. You can also call the court clerk for the county where the person lives or lived and ask how to access the court records.

To find a person by name, visit a free people search directory such as Zaba Search, Find People by Maiden Name or AnyWho. Enter the person's first name, last name and state or city into the search bar, and see what the database comes up with. Repeat the search using all the past and current names you pulled up. If a match is found, the search directory usually gives you the person's address for free. However, you typically have to pay for additional information such as the person's email address, relatives and social networks.

Facebook users can add maiden names, former names and nicknames to their profiles in addition to their current details. If your friend has done this, then a simple search against her former name should bring up her social media profile. While you're browsing social media, be sure to check out any schools, clubs or workplaces that the person was connected with. Even if you don't strike gold and find your friend's profile, there's a chance that you'll connect with old associates who have some information regarding her whereabouts.

In most states, it's perfectly possible for someone to start using a new name at any time, without having to register the change with any official body. For example, someone might take his partner's name even if they are not married, or couples might "double-barrel" by hyphenating their last names. For this reason, you might find that a record of the name change simply does not exist, and you’ll have to complete your investigations using only the person's original name. If all else fails, hire a private investigator to do the sleuthing for you.