Typically, the new lawyer will have you explain the reasons for your wishing to change counsel. It is important for all lawyers to find out why it is you're seeking to make a change. After determining that the new attorney meets your criteria and the attorney is willing to take on the case, a discussion relating to the transition of your file to the new office would take place.
It is generally unnecessary for you to contact your prior lawyer and explain that you going to be making the change, although you can if you wish. Instead, the new attorney would make all the necessary arrangements with your current attorney to have your file transferred to his or her office. A letter is generally sent specifically stating that the former attorney should make no attempt to contact you personally, but simply forward the documents.
For many types of claims, your first attorney will receive a fee for services rendered once the case is resolved, either for the actual time put in by your attorney or the "value" of the attorney services to the overall result obtained. This will vary depending upon the state in which you retained your lawyer.
If your attorney settled the case without your permission, and you have not yet executed the settlement and release agreement, and you're unhappy with the settlement, you should tell your attorney that you do not wish to proceed with the settlement. If a check has previously been forwarded to your attorney, it is a simple matter to return the funds.
Send your attorney a note letting him or her know that you've been trying to reach the office and speak with him or her, and would greatly appreciate a return call as well as a written update and specific responses to your questions. The letter creates a paper trail of communication with your attorney. The longer the attorney is unresponsive, especially after sending him or her a letter, the stronger a case for malpractice may be.
The most common theory of liability used in malpractice cases is negligence.