VSR $ cannot be deleted due to variant data in purchasing organization $

What causes this issue?

Variant data still exist (purchasing data or partner functions) for the
vendor sub-range in a purchasing organization.

System Response

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

How to fix this error?

First delete the variant data.

Error message extract from SAP system. Copyright SAP SE.