If you are the account holder
Open the joint-account transaction and remove theFamily mark from the transaction or allocation that should be personal.
That personal part is removed from family expense reports. Your partner still sees that money moved from the joint account, because the shared account balance must stay correct.
In your partner’s space, finerd represents the personal part as money moving from the joint account to your family member account. The merchant and description should be hidden or marked as sensitive so the transaction does not expose unnecessary personal context.