Legal Question in Family Law in California

I assume by "granted a bifurcation" you mean granted a bifurcation AND a judgment of dissolution was entered. If my assumption is correct, the answer is "no." You cannot reverse the judgment once it is entered. Of course you are free to get married to each other again, which would have almost exactly the same effect. The only difference would be if you crossed from one tax year into the next while divorced, or other financial events occurred that would be affected by whether or not you were married.