How to replace/add approvals in Change Worflow

Hi Expert,

We may need to insert an additional approval phase in our Change Workflow. My concern is that how to add an approval to a worflow phase? I have already defined a new Approval Definition in Approval Def table.

I could not define it in the worflow.

1. Click on Workflow Phase (Sample phase: Phase - PMO Approval)

2. Click on Approvals Tab of the Phase - PMO Approval

3. Click on "Add"; a window wil open "Add approvals", but it shows Blank selection.

Please guide as it seems I'm misisng a step here? We are having SM 9.33 with Process Designer.

Thank you in advance.