To add update an approver to an existing policy that does not require an new version or a minor update when using the Approval workflow setting, you will need access to the Management Console and the Policy Management.
Go to Search policy, as the policy has been published ensure Policy Status is set to Live and change the Workflow status to Released
Select the policy and click on the Document tab and select Update policy document then select User current document
Within the Approvers field, you can remove existing approvers by selecting the 'x' next to their name.
By clicking in the Approvers field you will be presented with the full list of users who are available to approve policies (these are users how have been given the Policy approvers permission) and by starting to type in the approvers name, the list will dynamically filter the list until you have found the correct approvers. Policies can have multiple approvers.
Selecting Send current policy document will now send the current policy through the approval workflow