This is an internal company decision best addressed by an Operating Agreement. If you have not adopted an operating agreement or held an organizational meeting, then the LLC members don’t have a formal agreement on adding or removing members.
Once you’ve held the organizational meeting and adopted an Operating Agreement, then the Operating Agreement should spell out the necessary steps for adding and removing of members. At the least you should document the change in writing and have all parties sign that document.
Once you’ve done that, then you will notify the State of the change by filing an updated Annual Report (we can do this for you).
NOTE: You might be able to file an “Early” Annual Report if you want the state database to be updated immediately or some states will require you to wait until your next Annual Report is due. If your state does not list Members or have an Annual Report then you will simply need to keep internal records of the change per your Operating Agreement.