我感觉是这样（请真正懂的人更正）：

If you have a Traditional IRA account that has some pre tax money inside already ,。你可以去别的银行再开一个新的 traditional ira account. Use this brand new account to do backdoor Roth ira conversion.

这些退休帐号，和checking 帐号一样，可以有许多个，怎么方便怎么来。