I was going to use DMT to do this but all I seem to be able to do is add oper and opdtl but it wants to delete the oper not just the opdtl record.
If you have a newer version of the 10.1 DMT tool, of which I can’t find the release notes.
You can add in the column RowMod (Opdtl#RowMod) with the value of “D”, and then run it in update mode and it should delete the resources.
Seemed like it should work, but doesn’t want to co-operate. It took ECOOpDtl#RowMod and processed the file but no change to PartOpDtl. Using DMT 4.0.19.0 for 10.1.500.2 at the time of testing.
@jgiese.wci - Can you elaborate on your update tool? I’m trying to delete 2000 resources from MoM BOO’s. DMT took the ECOOpDtl#RowMod = D column in update mode, but no change to my MoM. Epicor support said it’s not possible via DMT, which I have a hard time believing, and I haven’t been able to get a response from the DMT team directly.
If I lose patience waiting on Epicor, I’ll probably head down the path that my former co-worker suggested of exporting op details via BAQ, deleting the entire op via DMT (along with assigned materials), and then re-adding it minus the resource.
I don’t have it anymore but it was pretty simple. I took my DMT template, looped through it and used REST calls to remove the resources I didn’t want.
Joshua - Easy for you! 
REST is definitely on our new skills to get list here…
Epicor support now states there is no way to do it via DMT in 10.0, FWIW…