我认为LogonUser和ImpersonateLoggedOnUser的组合会对您起作用。这应该会更改当前进程正在运行的用户帐户。正如GBN提到的，在更改登录凭据之前，您可能必须断开所有活动连接。

使用Scott W建议的方法，这段代码对我有效。其中一些可能需要根据您的特定网络环境进行调整。

procedure ChangeLoggedInUser(username, password, domain: string);
var
  creds: Cardinal;
begin
  try
    if LogonUser(PChar(username)
        ,PChar(domain)
        ,PChar(password)
        ,LOGON32_LOGON_NETWORK
        ,LOGON32_PROVIDER_DEFAULT
        ,creds
      )
    then begin
      ImpersonateLoggedOnUser(creds);
    end
    else begin
      RaiseLastOSError;
    end;
  finally
    //wipe the memory for security
    FillChar(username,SizeOf(username),#0);
    FillChar(password,SizeOf(username),#0);
    FillChar(domain,SizeOf(username),#0);
  end;  //try-finally
end;

这段代码可以这样命名：

...
//at this point i am logged in as whoever is logged into the local machine
DoSomethingMundane;

//change credentials of the current thread
ChangeLoggedInUser('importantuser','secretpassword','mydomain');

//now my process will be logged in as "importantuser"
DoSomethingThatRequiresCreds;

//go back to normal
RevertToSelf;

//now my process is back to normal
DoSomethingMundane;