An advocate is someone who speaks on behalf of another person
An Advocate can recommend, push for something.

Individual Advocacy Support to....
Negotiate with service providers
Follow up discrimination complaints
Get access to accessible housing
Assist with criminal justice issues

Systemic Advocacy addressess issues like....
Equitable access to taxis
Bulding regulations to create accessible housing
Entitlement provision for disability support
Getting younger people out of residential aged care