Depending on permissions, you may not have access to "Force"

1. Go to Tools-Purchase Orders

2. Right click the PO you wish to refresh and click "Refresh PO from USAS" and select the option that is needed

NOTE: You can multi select by either putting checkbox next to each one, clicking CTRL and selecting multiple lines, or using shift to select a group. 

Auto Refresh: If there was a change in USAS, it will bring in a new PO image

Force Refresh: Regardless of change in USAS or not, it will bring in a new PO image

3. Once shows completed in upper right hand corner, the PO has been refreshed in SCView