There are two different ways to do this, follow the steps below.
Option 1
Click CorePersonnel, Maintenance, Personnel Profile.
Select employee in question.
Click Post Profile, Appointment Details, Cost Allocation.
There is an option to add another cost allocation.
Option 2
Click CorePersonnel, Maintenance, Personnel Profile.
Select employee in question.
Use the Status Detail drop-down and select Cost Allocations.
There is an option to add another cost allocation.