Recursive function issue in PHP overwrites result when going to a new child in breadth

I have a database structure as following:

+----+-----------+-----------+
| ID |   Name    | Parent_ID |
+----+-----------+-----------+
|  1 | 123a      | 2         |
|  2 | Microsoft | 3         |
|  3 | Apple     | 14        |
|  5 | IBM       | 14        |
| 14 | Amazon    | NULL      |
+----+-----------+-----------+

I want to retrieve an array of all children of a certain ID.

So if I launch my function with ID = 14, i want to get the following result:

array (size=2)
  0 => 
    array (size=3)
      'orgid' => string '3' (length=1)
      'name' => string 'Apple' (length=5)
      'parent_id' => string '14' (length=1)
  1 => 
    array (size=3)
      'orgid' => string '5' (length=1)
      'name' => string 'IBM' (length=3)
      'parent_id' => string '14' (length=2)

This is the code I have so far:

    function get_all_children_from_tree($orgparentid, $childrenArray = null)
    {
        $CI = get_instance();
        $CI->load->model('organization/organization_model');

        $allChildrenOrgs = $CI->organization_model->getAllChildrenForParent($orgparentid);
        if (empty($childrenArray)) {
            $childrenArray = [];
        }

        foreach ($allChildrenOrgs as $org)
        {
            $org_id = $org->org_id;
            $org_name = $org->name;
            $org_parent_id = $org->parent_id;
            $arr = array('orgid' => $org_id, 'name' => $org_name, 'parent_id' => $org_parent_id);
            array_push($childrenArray, $arr);

            if (!empty($org_id)) {
                get_all_children_from_tree($org_id, $childrenArray);
            }
        }
        return $childrenArray;
    }

Going depth first on the first child works great and gives me the correct result, but as soon as I enter the 2nd child of the root (IBM in this example), the resulting array is returned to its original value at the point where the recursive function is called. And thus all the children get expelled from the result.

For example, the result with my code and the example data as provided above will be:

array (size=5)
  0 => 
    array (size=3)
      'orgid' => string '14' (length=1)
      'name' => string 'Amazon' (length=6)
      'parent_id' => NULL
  4 => 
    array (size=3)
      'orgid' => string '5' (length=1)
      'name' => string 'IBM' (length=3)
      'parent_id' => string '14' (length=2)