Best practice Revision on changing item attribute

What is the best practice if an item was revised to change from serial control to lot control or vise versa? Would standard protocol dictate that this could not be a revision change but rather a part number change altogether? If it is acceptable to have a revision change a part from serial control to lot control, how would this best be implemented for historical parts. For example, items in inventory, items in transit, items in wip, items sold to a customer.

We recently had a drawing revision change that included remove serial control and adding lot control. We currently have items in transit, on hand and in wip. Should we not allow this type of revision change and request a new part number all together?