&1 cannot be deleted; it is used in Basic Material Composition of &2

What causes this issue?

You want to delete a compliance data object; however, the validation
check has determined that the object is used as a reference in the basic
material composition of another compliance data object.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.