Unable to delete object & (&) because it is still in use

What causes this issue?

The specified object could not be deleted because it is still being
used in other objects. These would be inconsistent if the object were
deleted.

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?

You can only delete the object once you have deleted its uses in other
objects. You can check which other objects are still using the specified
object by means of the where-used list.

Error message extract from SAP system. Copyright SAP SE.