+1 to kinnem's post.
Since you went to FT this past summer, I am assuming you are still AFROTC.
Be prepared to discuss why you are going from a tech field to non-tech. Most importantly will you still graduate on time?
Changing majors in your spring jr. yr. could delay your graduation. Have you investigated with your academic advisor if switching majors will allow you to graduate May 2014?
That's the thing. AFROTC and the AF is predicting from a manpower need you will commission May 2014, not Dec. or May 2015.
Can you do it? Yes.
You will need the command approval to switch from tech to non-tech. That means going through the chain of AFROTC. Contact them ASAP.
Be prepared to defend why you are switching to a non-tech major at this late stage. It is a late stage since you are close to 2/3rd of the way through college.
It never hurts to ask. It only hurts later on when you realize you should have asked in the 1st place.