An actual attorney is a person who is assigned to act on behalf of another person in business, financial or personal matters.
A proxy is appointed by issuing a power of attorney, usually by the person to be represented.
The actual attorney does not have to be a barrister, which is another name for “lawyer”. The first makes decisions for the principal, and the second advises and represents the client, but does not participate in decision-making.
Sometimes the courts can issue an individual power of attorney for another person if he has become incapacitated.