BAPI or FM to assign approver manually for Post Parked Document

Hi All,

Can you please suggest any BAPI or FM to assign the approver for Park Document Workflow. 

I want to achieve the same functionality which I get while executing the work item from the SBWP. It asks for the below options and after selecting “Assign Approver Manually” it show the below window for selecting the approver.

I want to it via custome code for one of th report so can you please suggest any BAPI or FM which would be work same as "Assign Approver Manullay" tab.

Regards,

Mayank