I would be curious to know if this could be done as well, but likely is done with INPA or specialized BMW software to deflate a particular corner.

Arnott said to lower the strut down (while inflated) and crack the air line fitting open which will bleed off the air on that corner. Seems sketchy to me personally, I haven't done it yet. I only have experience replacing an air strut on the driver side of my car which had already deflated due to aged rubber.

Here was the DIY video I made for that, maybe will give you an idea of what's involved with the brass fitting and airline in the strut housing:

https://www.youtube.com/watch?v=yW2NhlJ1ahM