Perhaps you have the flexibility to reschedule tasks that are contributing to overallocations, but you don’t have extra resources. In this case, you can resolve resource overallocations by adjusting tasks.
Delay a Task Manually
Delay a task manually if you want to delay one task at a time, see exactly how this delay affects the project schedule, and adjust the delay, if necessary. Delay a task manually until a resource has time to work on it.
Delay Tasks Automatically
Delay tasks automatically if you want to resolve a number of overallocated resources all at once. Delay tasks automatically by leveling the overallocated resources. Leveling delays or splits certain tasks in your schedule until the resources assigned to them are no longer overallocated.
Cut a Task’s Scope
Cut a task’s scope if you want to avoid rescheduling a task or increasing its duration. Decrease the amount of work required for a task by cutting its scope.
Split a Task
Split a task if you want to schedule a resource only for the exact time periods that the resource will actually work on a task. Alternatively, you can use this method to assign a different resource to each portion of a task.