After some bad experiences in a master's program, I decided to become a PhD student in the same program. My plan was to finish a paper and leave as soon as possible, meanwhile earning the recommendations that my bad early experiences prevented. That's basically been the situation for a couple years now - longer than I ever expected. At this point, I'm finally finish my projects and I've presented at a couple conferences. I genuinely like the professor I'm working with now. However, I never intended to specialize in this research area; the idea of doing my PhD in this area is very disappointing to me. And (selfishly?), I very much want to move to a new institution.
At this point, I'm not sure what to do. My ideal situation would be to finish my current projects and move to a new institution to work in a field I was more excited about. However, I'm afraid that if I reveal my desires the professor I'm working with will try to sabotage me. I'm also concerned that leaving now will look strange on a graduate application: why admit a quitter? I'm also starting to feel a little old to be starting a new program.
I'd really like to just be done with all this, but the question I keep asking myself is, "Why get a PhD in something you're not interested in?" Maybe, though, there are good reasons.
I'd appreciate any advice you may have.
Nothing is preventing you from trying PhD in another laboratory at least one or two times. It is appropriate, in some cases may be recommended and is usually accepted as a normal case.
Maybe if it is an adjacent laboratory next door, a potential new supervisor may not want to conflict with your former supervisor, but this seldom expands outside one institution, and even there largely depends on personalities involved.