ISSUE
If you are looking at changing the ‘Default Action Account’ Rus-As Accounts for a server, even if you use an account with the right access you may find that the server greys out.
My findings have found this is more common on Domain Controllers or Servers in OU with blocked Group Policy (If you are using Group Policies to determine access). Meaning that the account setup when you installed the agent doesnt have the access to make changes to the Health Service setup.
RESOLUTION
Use HSLockdown to add the Action Account to the Health Service. You can do this using the command:
c:\”Program Files\System Center Operations Manager 2007″\
hslockdown “Management Group” /A “DOMAIN\USER NAME”
Note: I put in the exclimation marks (“) just to point out if you use spaces they will be required to run any commands.