Mr_Fairplay

Are you asking if it's possible that a soldier can skip ranks? Because, yes it is. I did it when I was going into boot camp because of my ROTC training. And another guy who went to boot camp with me skipped three ranks because he had done four years in college. That was back in 96 so I have no idea if things have changed since...

Yes, that is exactly what i was looking for. Allow me to explain a bit so you know where i'm coming from, say in the future by a hundred and fifty years, there was a huge intergalactic war and one HUMAN soldier was exceptionally good and did a ton of things to stop the war and bring about peace, so for his heroic actions, could he be promoted by skipping ranks, like from Commander to an Admiral?

It's harder as you go up in the ranks. There are the brevet promotions, which are largely honorary, and battlefield commissions, which can be revoked later. But there is surely some precedent for outstanding merit being rewarded. I say go for it!