You can modify a policy that is applied to one or more objects
to change the properties on all of the objects.
To modify a policy:
Start System Manager: On the Start menu, point to
Programs, point to Microsoft Exchange, and then click
System Manager.
Under the organization or administrative group item,
right-click System Policies, right-click the policy you want
to modify, and then click Properties.
Use the tabs to modify the policy.
Right-click the policy, and then click Apply now to
apply the changes.