You own the sentence. It doesn't own you.
I stop trying to fix what isn't working. I start a new sentence.
However, I am far more comfortable with writing than I am with knitting. On the current scarf attempt, I recently hit the mother lode of all knots. What was once yarn became a relentlessly twisted wreck of unforgiving fiber.
Being a newbie knitter and a psychotic over-achiever, I refused to admit defeat. I spent hours trying to untie the knots. Hours.
Then, I finally realized: I own the yarn. It doesn't own me.
I cut the cord. Literally. Cut the knot out, tied the yarn back together, and took off knitting again. Now, this may not be the approved approach in knitting, but this is a scarf -- not a nuclear power plant. One glitch won't end the world.
The next time you hit a creative roadblock, remember: If at first you don't succeed, try, try again. If that doesn't work, cut the knot.