MPoni123 – I would like to add comment to Zena's previous response.
You may register to retake any section you need at anytime, if you found out you fail (which I hope you don't fail).
However, you must consider the fact that register for two sections in separate NTSs will cost you more than register two sections in one NTS. Again if you take more than one section in the October/November window, you should wait to get all results (either pass or fail) before you go ahead and register to retake any section you fail.
Remember that there is a re-examination fee, in addition to, each section test fee every time you register. Typically (not all states are the same), register one section is $60 fee, register two sections is $75 fee. Thus, if you register two sections separately you will pay $120 instead of $75.
I hope this helps.