You can withdrawl your agreement by calling the bondsman and telling them that you no longer want to be on the bond as you feel the ``criminal'' will not show up to court. You can sign off of the bail but they may arrest your friend.
A bail bond is a surety bond, which is posted by a bail bond company to the court as a guarantee for an arrestee's appearance at all court dates. The court will release an arrestee from detention upon posting of the bail bond.
Bond Duration Explained Bail bonds in California are valid for the life of the cases unless you miss court or get rearrested. Then, depending on the circumstances, you may need to post another bond.