Depreciation key &1 cannot be deleted

What causes this issue?

Depreciation key &V1& in chart of depreciation &V2& cannot be deleted,
since it is still being used in at least one asset class (asset class
&V3&).

System Response

Depreciation key &V1& is not deleted.

How to fix this error?

Change the depreciation key in asset class &V3&.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.