Yes, it is possible. We have such a guy in TACAMO right now. He had an AF pilot slot, was sent to Pcola, AF decided they had too many pilots in training so they forced him and a lot of others around him to become navs since they were already there. Down the line they decided what the AF did wasn't legal so they offered him a bunch of choices, and he chose a non-flying job of his choice with preference for pilot selection a little ways down the road. Skip ahead to a little ways down the road: He needs a waiver for being very slightly too old to start UPT, AF won't give it to him. He gets a job offer to fly 16s for a guard unit but needs to be let out of his AF commitment a few months early, guess what, AF won't let him go. He ends up later working for an admiral who gets him an SNA slot, and ends up getting E-6s out of that (ironic, ain't it, goes through AF flight training after all that BS).