How To Fix UD345 - Entity type & is assigned to more than one object type.

SAP Error Message - Details

• Message type: E = Error

• Message class: UD - EDM - Enterprise Data Model

• Message number: 345

• Message text: Entity type & is assigned to more than one object type.

What causes this issue?

You want to change from an entity type to the corresponding object type.
This is not possible because the entity type is assigned to more than
one object type.

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?

Make an unique assignment.

Error message extract from SAP system. Copyright SAP SE.