How to get role from parent role through API? Explanation : I have LC where particular role (For Eg: "APPROVER")is assigned to a state. For APPROVER role another role (For Eg: GRAPHICAL APPROVER) is assigned as participant. Now from team I can get on

How to get role from parent role through API? Explanation : I have LC where particular role (For Eg: "APPROVER")is assigned to a state. For APPROVER role another role (For Eg: GRAPHICAL APPROVER) is assigned as participant. Now from team I can get only APPROVER role. Now How do I get GRAPHICAL APPROVER role from APPROVER role? Is there any AP available? Please help