Nothing easier. You just need the right gear already installed and ready.
Here's the problem. your neighbor's solar panels are UL 1741 compliant, meaning they are only capable of "Grid Following" - for safety reasons they actively sense the presence or absence of the outside power grid, and shut off altogether when the external grid is absent.
Fortunately, Superstorm Sandy happened. And lots of smug, solar-owning East Coast business leaders and influencers got a rude awakening and told the market "Fix this!"
Turns out it's not an easy problem.
You'll need to create a local "grid" that looks, walks and quacks like a grid to a UL 1741 grid-tie inverter. A random inverter won't do, you'll need a grid-forming inverter such as a Schneider 40xx. This will fool the solar panels into powering up and doing their thing.
At that point it's a simple matter of disconnecting your neighbor's UL 1741 inverter from the utility and connecting it to your micro-grid. (remember not to backfeed the grid here!)
However... To form a grid, you need a power source. You need a battery for other reasons - as a buffer for a bunch of things, and since you have a battery, might as well use it for that power source. All the commercial gear that does this is built around that assumption, so you're stuck with it unless you want to get an EE degree and build your own.
Once you have established your micro-grid, it's as easy as rewiring your neighbor's UL 1741 grid-tie inverter to talk to your micro-grid instead of the utility grid. Again, don't backfeed the utility grid!
You also need to isolate your own microgrid from the utility grid. There are some sophisticated ways to do that. However I'm all for just using a utility/generator interlock on a "critical loads" subpanel (and by the way if you put every circuit in your house on it, I won't tell ;) You can't use the main panel for that, because certain loads have to be on the utility side.