Set-SCSMRunbookActivitiesToRerun.ps1

# Define query criteria
$Class = Get-SCSMClass Microsoft.SystemCenter.Orchestrator.RunbookAutomationActivity$
$InProgress = (Get-SCSMEnumeration ActivityStatusEnum.Active).id.guid
$Yesterday = (get-date).AddDays(-1)
$cType = "Microsoft.EnterpriseManagement.Common.EnterpriseManagementObjectCriteria"
$cString = "Status = '$InProgress' and LastModified > '$yesterday'"
$crit = new-object $cType $cString,$Class

# Get activities
$Activities = Get-SCSMObject -criteria $crit

# List out all activities
$activities | select Id,Title,LastModified

# Set activity status to ReRun
$activities | Set-SCSMObject -Property Status -Value "ActivityStatusEnum.ReRun"