Insert or edit work plan tasks on an activity in the Tasks table window on the Plans tab of the Activities and Tasks (SP) application.
If a current work plan is based on a job plan, all task and plan data is copied from the job plan to the work plan. The following information also is copied from the activity to work plan tasks:
address information
customer
customer agreement and price schedule
customer charge account and cost center
customer PO number
revision number
You can add or edit plan tasks until the activity is closed, but you cannot delete tasks from an approved activity or from an activity on which actuals were reported for the task.
After you close the activity, add or modify tasks with the Edit History Activity action.