Available Liferay 7.4 U26+/GA26+
You can remove relationships from both draft and published object definitions. Removing a relationship permanently deletes its field from the related object definitions. For published definitions, this can affect many records.
For versions before Liferay 7.4 U26/GA26, users cannot delete relationships included in an object at the time of publishing.
Follow these steps to remove relationships from published object definitions:
Open the Global Menu (), go to the Control Panel tab, and click Objects.
Begin editing the desired object definition and go to the Relationships tab.
Click the Actions button () for the desired relationship and select Delete.
In the dialog window, enter the name of the relationship and click Delete to confirm.