I found this article that explains how to convert Parallels Desktop virtual machine to VMware Workstation
Convert Parallels Desktop virtual machine to Vmware Workstation
When I downloaded VM vCenter Converter Standalone it no longer supports other Virtual Machine systems

I found this article in VMWare docs to Import a Parallels Virtual Machine into VMWare Fusion, and I found a VMware Knowledge Base article on moving between Fusion and Workstation.
Is it possible to go straight from Parallels to Workstation, or do I need to go through Fusion first?