Selecting approach route in flight and automatic approach route selection

Hi there, i have a couple of questions about selecting an approach route in flight.

I am usually selecting an approach route already when preparing the flight plan. This works quite well. The flight plan being automatically set in your flight computer with the approach route that i have selected. This is quite handy as you can just use AP in GPS/NAV mode and follow the approach route switching AP to APR on final. It also tunes the ILS frequency automatically, very comfortable.

However with the real weather feature the wind at destination airport can change significantly after a long flight. And sometimes i am ending up landing downwind. Once i had 20 knots downwind and the runway was short enough to make me sweat a bit.

So my question is, can i actually switch to a different runway, and a different approach route in flight? Do i have to program the other route into the flight computer manually, with all its waypoints, or is the flight computer smart enough to pick up new route with all its waypoints?

And - how is actually the option “automatic” approach route working? I have never tried this option yet. It seems like the flight computer is not being programmed with an approach route at all when this option is used. Instead the flight plan in the computer just ends directly at destination airport with no any approach route. What happens when you are approaching with “automatic”, does the ATC assign you one of the approach routes depending on your position and runway in use? And if so, does it update the flight plan in the computer, or am i supposed to do that myself manually?

Im little bit affraid of using that feature, as im thinking that ATC will assign me some route but my flight plan will not be updated, and as i usually don’t have all the approach charts by hand, i will have no idea what would be that particular route and how to follow it properly.