Remove SCCM Child Primary Site from a Hierarchy.

Remove SCCM Child Primary Site- Step by Step...

CEN - Primary Central Site
PRI - Child Primary Site
SEC - Secondary Site

Here is the procedure how to remove PRI SCCM Child Primary Site from its CEN SCCM Parent Site. All steps have to be performed from the Central Site 
Server except the last one.

First step is to login to the Central Site Server and to delete PRI child site address from SCCM console.

Next step is to execute Preinst.exe which is located in C:\Program Files (x86)\Microsoft Configuration Manager\bin\i386\00000409 folder:

Execute Preinst /dump command. It shows SCCM sites in SCCM Parent Central Site. The target is to remove PRI Child Primary Site.

Delete jobs for PRI site: Preinst /deljob PRI

Delete PRI site: Preinst /delSITE PRI CEN

Execute again Preinst /deljob PRI to delete any job in meantime.

Executing again Preinst /dump command shows that PRI Child Primary Site has been removed from SCCM Parent site.

Now logon to the Primary Site Server and remove settings from Report to parent site to Central site in SCCM Console.

Finally you can see that all locked out items have been removed. All Software deployments packages, Advertisements, OS deployment packages, and Task Sequences have been inherited form SCCM Parent site into SCCM Child Site and can be modified.

The Site can be uninstalled using Configuration Manager Setup Wizard.