You can directly edit Active Directory in both Ldp.exe and Adsiedit.msc. Only experienced administrators should use these tools to edit Active Directory.
Note that Ldp.exe shows the values in hexadecimal. Adsiedit.msc displays the values in decimal. The flags are cumulative. To disable a user's account, set the UserAccountControl attribute to 0x0202 (0x002 + 0x0200). In decimal, this is 514 (2 + 512).