if you can find a second year slot I suppose. Not sure if there are contractual obligations you would have to deal with. Would be very dicey to do this for many reasons. You should be interviewing for jobs soon, who will vouch for you? Will you be able to keep a good relationship with current fellowship program if you do? Training varies from one place to another so you may get a mixed bag once done (maybe for the better, maybe for the worse). You should really think this through.
A lot of this, I would think, would take coordination with program directors. So best disclose to your program and have them help. Good luck.