Primavera doesn't have a feature to split a planned activity. It does have "Suspend" and "Resume" fields for statusing an activity with a break in the middle. But as for splitting planned activities in Oracle Primavera, we have to get creative to make it happen. One way to split an activity is using User Defined Fields to display the split on the Gantt Chart. I'm using a special Gantt bar -
User Defined Fields in P6 : Tutorials and Articles
Primavera P6 UDFs or User Defined Fields help you customize P6 to your needs. Read our Primavera P6 User Defined Field Tutorials and Articles.