Mass update of main report for all linked reports in SSRS

I need to change the  main report for 800+ linked reports.  Does anyone know of a way to script this?

I have tried updating the Catalog table by replacing the ParentID and LinkedReportID both individually and at the same time the report will disappear from the folder location, but it is still there with the correct path if you search for it.

Needless to say I would rather not update the linked reports manually.  Any help is greatly appreciated.

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//Jeff