Your network contains an Active Directory forest.  
You add an additional user principal name （UPN） suffix to the forest.  
You need to modify the UPN suffix of all users. You want to achieve this goal by using the minimum  amount of administrative effort.  
What should you use（）

Your network contains an Active Directory forest. The functional level of the forest is Windows Server  2008 R2.  
Your companys corporate security policy states that the password for each user account must be  changed at least every 45 days.  
You have a user account named Service1. Service1 is used by a network application named Application1.  
Every 45 days， Application1 fails.  
After resetting the password for Service1， Application1 runs properly.  
You need to resolve the issue that causes Application1 to fail. The solution must adhere to the corporate  security policy.  
What should you do（）