If I transitioned from active duty to NG, is it possible to transition back?

I cant see why not. I imagine there will be a bunch of hoops to jump through.

Easiest answer is: Yes, talk to a recruiter. The long answer is yes.. get ready for a very long process.

I just switched back to AD. It wasn’t to much you just need a Conditional Release signed by the first O-6 in your CoC. Talk to the nearest AD recruiter and he should be able to assist you. Watch out because certain MOS are not available to prior service. Good luck and hope your switch back goes as easy as mine.