Plkease note that the changeScheduleOwnerAndRunBy will reassociate all the reports and alerts that were created by a specific user to the new user. Meaning if you want to update the report to show it ran from UserB instead of UserA and you run this script, if UserA created other reports or alerts, they will be updated as well. It is an all or nothing user change.
If you want to just make this change to one or two reports it is best you follow James's original suggestion of editing the schedule so it updates the owner name.
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