Final answer:
The individual authorized and consenting to represent another's interests is known as an agent. Agents play a vital role in various professional fields, including entertainment and politics.
Step-by-step explanation:
The individual who is authorized to, and consents to, represent the interests of another person is called an agent. An agent acts on behalf of another person, referred to as the principal, in dealings with third parties. This relationship is crucial in business and law, where agents can perform tasks ranging from making deals to lobbying. Alaine Alldaffer provides an example of this, describing how agents represent actors and pitch them to casting directors. In the context of lobbying, an individual who does this as part of their job is known as an in-house lobbyist, differentiating from a volunteer lobbyist who may perform similar actions without compensation.