How to increase time to process "ACTIVE" interface??

Hi,

    Slowly trying to learn more about PI / PO. Currently our PO system every one hour processes "ACTIVE" interfaces - occupying more space with messages. And at sometimes when we come to office next day server goes down and creates problems. I want to increase this process time to every 10 Hours.
Please can anyone suggest me where can i do this change?

Would really appreciate your help. Thank you.

Rup