If you have not selected a license manager or wish to point to a different license manager on the network, you may do so via an environment variable. When you start your ESRI applications, they will use this environment variable path to find a license manager.
Go to your Control Panel and click on System. Choose the Environment tab.
Create a new variable and set the Variable type = ESRI_LICENSE_FILE.
Set the Value = @<host> for your new license manager. (eg. '@mycomputer')
Click Apply and the new variable will be listed under User Variables.