I'm not near my laptop so I can't share an example flow for you, but I can try to explain it.
First up, here is how it was described in the release blog post:
The new Link Call node can be used alongside the Link-In/Out nodes to create subroutine-like flows.
If you have a flow that starts with a Link-In node and ends with a Link-Out node that has been put into its new ‘return’ mode (giving the node a different icon), the Link Call node can be used to pass that flow a message and the result is passed back to the calling node.
As an alternative to using subflows, this is great for creating little utility flows that you want to reuse in multiple places.
Hopefully the image helps give you a sense of what that all means.
If that doesn't help, I'll share an example flow in the morning.