How to add additional employee types in Workforce Planning?

Summary:

In the Out-of-the-Box Workforce Planning, when adding a new hire requisition, the options we have to tag the new hire for the Employee Type property are: 1) Regular, 2) Temporary and 3) Contractor. However, the client wants to add some more types (Example: Contigent, Non Contingent etc.). Unfortunately, the Employee Type is tagged to the SmartList OWP_EmployeeType which is non-editable.

Is there a way to update this SmartList OWP_EmployeeType so that we can add more values?

Content (please ensure you mask any confidential information):

Version (include the version you are using, if applicable):

Service: Enterprise Performance Management Enterprise Cloud

Business Process: Planning