Debra --
There's at least a couple ways to manage risk on a task:
1. Increased the Duration of the task to absorb a potential late finish.
The risk of doing this, however, is that you increase the work. Remember
also that work fills the time available to do it, which is human nature.
2. Add Lag time to the dependency between this task and its successor task.
To add Lag time on a dependency, double-click the link line between this
task and its successor, and enter a Lag value.
Hope this helps.