Sync record smart service

You need to add a loop to your process model as described here: [View:https://docs.appian.com/suite/help/23.2/Sync_Records_Smart_Service.html#sync-more-than-1000-records]

 You also have the option to trigger a manual sync on the record type directly. That saves you the hassle dealing with loop in the process model. 
Depends how large the record type is - you might have to do this after business hours.