Yield curve type & is still used

What causes this issue?

This yield curve type is used:
As a forward curve in a reference interest rate
In a scenario
Or:
Currency replacement is defined for this yield curve type

System Response

The selected yield curve type cannot be deleted.

How to fix this error?

Delete the assignment of the selected yield curve type (as the forward
curve in the reference interest rate, in the scenario), or delete the
currency replacement for the yield curve type.
To call up a complete list of where the yield curve type is used,
choose <ZK>Where-used</>.

Error message extract from SAP system. Copyright SAP SE.