How to customize approval process in ChaRM

Hello experts

In standard ChaRM scenario, the change manager will authorize the change and then different change transactions get created and processed. But if we want to have multiple people approve the change request, there is no standard configuration. The standard ChaRM will not allow multiple change manager exist in one change request. So here is:scenario

If I use partner function 'approved by' to allow multiple approvers in one change request, how can I configure the actions/status so that until all approvers authorize the change the change request can not go to next status?

SAP says ChaRM has customizable workflow. But I don't see where it is.

Any idea?

Thanks

Ming