A change of heart

I'm having a change of heart with the plot of book #3. I thought I had it all figured out months ago, but now that I'm a quarter of the way through writing it, I'm having second thoughts. I'm questioning whether or not my main character would actually do what I had planned for her. That's the funny thing about creating characters, at least for me anyway. They don't always turn out the way I plan. I like the character the way she is and I believe that with her I've created some great themes. The problem is that the way she is currently written, she doesn't fit my plot. What does a writer do when that happens? She changes the plot I guess! So much for making a plan and an outline before I began writing. That's a little frustrating, but I'm sure I'll get over it. Not all of it has to go, fortunately. With that said, I have a lot of work ahead of me and there's no time like the present.