You can switch the type of node within that node type at any time. This means that you can easily switch between different kinds of inputs, actions, values, or results.
Note that you cannot convert an input node to an action or result node, or vice versa.
Change the node type
To change the node type, simply click on the dropdown (which also displays the current active node type) next to the node name above the content editor. Once you click on it, a list with all possible node types appears. When you click on it, the node type changes.