If you are attempting to offboard a BMC CLM 2.1 NetworkContainer and it keeps complaining:
Cannot delete NetworkContainer : Primary because it is referenced by ResourceSet : <SOME RESOURCE SET HERE>
You have to bring up the Remedy User Tool, connect to the CloudDB, and open up form BMC.CLOUD:BMC_ResourceSet. Search for any entries MarkAsDeleted = NO.
Click on an entry from the search result, then click View Relationship.
In the relationship, DELETE RELATIONSHIP to the NetworkContainer (should be a CI ClassID of BMC.CORE:BMC_CONCRETECOLLECTION).
Try deleting the NetworkContainer again.