You should notify the attorneys formally, in writing, with some record that you did (fax receipt, certified mail, etc.) that you are terminating their services. Request a motion to withdraw that you can sign off on. You do not want them spending any unintended time on your case and they will remain your attorney of record until the motion is signed by the judge. Further, request a date certain that you can get your file from their office.
A weekly guide with tips and legal advice for each stage of the process.