Some clarifications

Let us start by clarifying some common confusions.
People often call real estate agents "realtors", but that is not necessarily true.
Realtors are all real estate licensees who are also members of the National Association of Realtors (NAR).
Licensees become members of NAR by joining a real estate board, which automatically affiliates them with NAR.
Most active licensees become members of a board by paying its fees, because it would be practically impossible to conduct business without access to real estate and tax databases, which the board provides.
But that is not mandatory, for example, an inactive licensee may choose not to be a member of a board, and save on fees, thus losing the ability to use the realtor designation.

Also, it is important to distinguish between agents and brokers.
Brokers are the only ones authorized to work independently and run a real estate firm.
Agents can only work under the supervision of a broker.
In the state of Florida, agents can only work for one broker.
Brokers are ultimately responsible for transactions, this is why most brokers carry Errors and Omissions insurance.
Both agents and brokers, if they pay fees to a real estate board, are authorized to use the "realtor" designation.