A call by reference is more similar to using a regular subVI then to using invoke nodes. It allows you to call different subVIs with the same connector panes, kind of like having a case structure with a different subVI in each case. It is similar to invoke nodes in that it loads VIs dynamically, which means you can use it instead of invokes, but you can't just replace an invoke with a call by reference.
To use it, you need to use open VI reference and wire a reference of a VI with a specific connector pane pattern. Then, wire that into the call by reference node and the connector pane will appear.
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