E905.700C, Re-assign Serial Number


I am trying to use the fuctionality in Epicor 905 to reassign the serial number of one assembly to the next level assembly. We are currently using full serial tracking and which is working fine.

When I check out the parent part to Engineering workbench & select the subassembly, the "reassign serial number to assembly" check box is disabled.

Both assemblies are currently being serial tracked and are working fine. Does anyone know if there are other set up items that need to happen in order for the re-assign serial check box to work? Epicor tells me "no", but they don't know why it's disabled either.

I have tried to mark it directly in the job as well, and it is disabled there too.

Thanks for any insight,
Liz Ewaschuk