How can I modify the Applications being monitored and the credentials used on each node without recreating the node?
You can change the credentials used for the node by editing the node itself, or modify the credential itself (update password, etc.) by going to [Settings -> Manage Windows Credentials]
Applications can have their own credentials, or inherit their credentials from the node. If the application has credentials specified you can change them by editing the assigned application [Go to application details page for the application you wish to modify and click "Edit Application Monitor". From here you can select which component, or select all components within the template and which credentials should be used. You can also use multi-edit (select multiple component and click "Multi edit") to change multiple components simultaneously.
To modify existing credentials use for applications (update a changes password) go to [Settings -> SAM Settings -> Credentials Library]
The one I am wanting to change is when you go through the discovery wizard and you get to the application monitor page, at the bottom. I guess I could edit the one I put in there and change it to the one I need to enter, but that seems counter intuitive. I can see where you change the test credentials in the node, but not the one that manages the applications being monitored...
The credentials shown in the Applications tab of the Network Sonar Discovery Wizard can be changed under [Settings -> SAM Settings -> Credentials Library]