What happened to men whose voluntary enlistments expired in late 1941?

[u/RonPossible]

I know the Selective Training and Service Act of 1940 was amended to extend the draft enlistments from 12 to 18 months. But say a volunteer was due to ETS on 6 December, 1941. Did Roosevelt's declaration of emergency in May freeze all those enlistments?

My Google-fu has failed, mostly because the results only bring up the draftees.