Update stock item BOM Details



I wonder if someone would be able to help me.  I have joined a company with an existing Sage200 setup and need to make some changes so Sage is setup to help us, the first task is to start using BOMs.

When we try to change a stock item's BOM Details from 'Component' to 'Built item' we get an unable to change status warning due to allocations against it and it cannot be made inactive:

Is there a way to change the BOM Details to Built item for an existing component and keep the item active?  We are not yet using works order processing this would be phase 2.

Many thanks in advance for any help