A real estate "agent" is licensed to practice real estate, but
only under the direct supervision of a broker. Without a broker to
oversee their activities and take responsibility for their actions
a real estate agent is not allowed to practice.
There is a trick of language here though, and it has to do with
Agency Law. By law, an agent is a person who acts on behalf of
someone else. A real estate broker is also called a real estate
agent. This is because they are acting as an agent for the buyer or
seller in a transaction. So the broker has the legal title of
"broker" generally and the title of agent in relation to his or her
client. A real estate agent working under a broker is an agent only
to the broker, the broker is agent to the client.