Modern Vespa

Rally 200. The autolube oil line has a pin hole and leaking oil into the frame. I have searched but don't see anywhere that explains how to disconnect the oil line from the oil reservoir. Do I have to pull out the gas tank to access? Seems like a simple task but I've spent ages trying to find the answer. Thanks.

without looking at mine I would have thought it has to be tank removal. Put some towels on your frame and you can normally lift out tank and place sideways to rest it . Having less fuel helps as it can feel a bit heavy if you got dodgy joints like me.

The procedure should be just as on the P models. Yes, you may have enough slack in the oil and fuel lines to just lift the tank/oil reservoir out of the frame; but most of the time you don't, and since you are changing the oil line, you might as well change the fuel line as well.
So, the short answer is to disconnect both oil and fuel lines at the carburetor and air box first, then guide them out through the frame rubber grommets; then disconnect their other ends at the tank/oil reservoir.
It is quite a messy job; so before disconnecting the lines, have some plugs/caps/screws to cap the lines and prevent excessive leaks.

Or if you have an air compressor you can just shoot the gas and oil still left in the lines out into a paper towel or something. Less mess in the bike this way.

You can switch off the fuel but not the oil. Remove the oil line at the carb and plug it with a screw to prevent oil leaking everywhere.