core/src/main/java/org/sakaiproject/nakamura/api/lite/authorizable/Authorizable.java
public void removePrincipal(String principal) {
        if (!readOnly && principals.contains(principal)) {
            principals.remove(principal);
            principalsModified = true;
        }
    }
public void removePrincipal(String principal) {
        if (!readOnly && principals.contains(principal)) {
            principals.remove(principal);
            principalsModified = true;
        }
    }
remove a principal from this authorizable.
@param principal