Package & is already in phase &, is not allowed to be deleted

What causes this issue?

You are trying to delete a package that has already been used for
starting a local currency conversion or runtime forecast. However this
package must not be deleted any more.

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?

Error message extract from SAP system. Copyright SAP SE.