Typically, you should send the attorney written notice of termination of services unless the contract requires other types of notice. If the attorney has entered an appearance in a Court action, the attorney will be required to file a formal withdrawal as well.
You can stop working with your lawyer, as you don't have a contract preventing you from doing so. Firing your attorney before a settlement pays out might not cut them out of the settlement entirely, though.
Even if the matter is not pending before a tribunal, the ethics rules of most states provide that a lawyer cannot withdraw until he or she has taken reasonable steps to avoid foreseeable prejudice to the rights of his client, such as giving notice to the client, allowing time for employment of other counsel, delivering ...
The best way to do this is to send a letter (email is fine). All you have to say is Dear Lawyer, I am terminating the attorney-client relationship effective immediately. Please send my client file to ADDRESS by DATE.
The Rules of Professional Conduct of the State Bar of California specify three circumstances under which an attorney must terminate a client relationship: (1) where the attorney knows or should know that a client is bringing an action, conducting a defense, asserting a position in litigation, or taking an appeal, ...
If you terminate your lawyer and do not hire another attorney, your old lawyer will have a right to place a lien on your claim. This means that you will owe your former attorney for the work they performed prior to the termination of your contract.
A lawyer who fails to respond promptly to your calls or emails, neglects to keep you informed about the progress of your case, or lacks clarity in explaining legal concepts may signal incompetence.
If your lawyer doesn't seem to be working on your case, sending a polite but firm letter expressing your concerns should get your lawyer's attention. Don't threaten to file a malpractice lawsuit or complain to the bar association; such threats will probably make your lawyer angry and defensive, not attentive.