An Advocator can be: One that argues for a cause; a supporter or defender
One that pleads in another's behalf; an intercessor.
An advocate is one who speaks on behalf of another person, especially in a legal context. It is used primarliy in reference to the system of Scots law, Anglo-Dutch law and Israeli law.
Implicit in the concept is the notion that the represented lacks the knowledge, skill, ability, or standing to speak for themselves. The broad equivalent in many English law-based jurisdictions is "barrister".