Removing Exchange 2003 from a Cluster Node
To remove Exchange 2003 from a cluster node, you must uninstall Exchange 2003 as you would from a stand-alone (non-clustered) server. However, only remove Exchange from those nodes that you no longer want Exchange to use. If you want Exchange 2003 to use the node (for example, as a passive node), do not uninstall Exchange 2003 from the node.
For detailed instructions, see How to Remove Exchange 2003 from a Node.