IdHTTP Get() With Authorization?

I'm using the following code snippet in a procedure with Indy 10 & D7

var
  InStream : TMemoryStream;

  BaseURL := Edit1.Text;
  IdHTTP1.Request.Username := Edit2.Text;
  IdHTTP1.Request.Password := Edit3.Text;
  try
    InStream := TMemoryStream.Create;
      try
        IdHTTP1.Get(BaseURL, InStream);
      except
        on E: EIdException do begin
        //Handle Indy exceptions here
        end;
      end;
  finally
    InStream.Free;
  end;

This works OK with authorization but if I change the URL and User/password
and call the above code again I'm getting a 401 exception. Is there
something I need to do to reset the IdHTTP before fetching another URL with
authoration?

-Andy