Update union schema: removing fieldset

Hi all

we are quite new in Adobe Experience Platform, in particular in the adoption of AJO.

We are designing a data Schema, that is enabled to partecipate in the Real Time Customer Profile acquistition and therefore partecipated in the main Union Schema: we have added a custom fieldset but now we need to rearrange these fields, some has to be removed, some added.

But when we try to remove a field, both via API or UI, we got an error: the fields cannot be removed as the are part of the union schema.

Is there a way to clean the data model removing such unnecessary fields or we are forced to keep them?

Many thanks.

Fabio