Assignes a new password instead of an expired one..
procedure ChangePassword(const NewPassword: string);
Use the ChangePassword method to change an expired user's password. In SQL Server versions prior to SQL Server 2005 only a database administrator has permissions to change an expired user's password. Starting from SQL Server 2005 you can change it using the ChangePassword method and SQL Native Client.
Note: Only an expired user's password can be changed using this method.