While it may not be that simple, it is possible. Under a handful of circumstances, California law allows you to withdraw your guilty or no contest plea if that plea was not freely and voluntarily entered. You seek this remedy via a California motion to vacate judgment.
Perhaps the most compelling argument for winning a motion to vacate judgment takes place when you feel you were coerced into entering your plea. This type of situation can arise in an infinite number of ways, but the most common probably lies in a threat.
When someone else has a stake in the outcome of your case…maybe because that person is the true culprit or because he/she wants you to take the fall for what should be a shared liability…and threatens to harm you or your family if you do not plea to the charge, you should prevail on a motion to vacate judgment.
Unfortunately, coming forward to admit this type of threat is scary and potentially subjects you to harm. But the good news is that prosecutors can take action against the individual who threatened you. They can file charges like criminal threats and obstruction of justice against that individual, allowing you to start your case over to try to receive an acquittal.