alright, it’s an arduous procedure, so follow very carefully…
How to replace the Pico 1 in your PicoCalc with a Pico 2W
- with the back removed, take out the pico 1 board
still with me? ok, now:
- insert the pico 2w in the spot you just freed
phew, you did it!
… 
in all seriousness, just be careful not to put pressure on the screen (it’s recommended you do this with the board removed entirely) and once you’re done just flash your favourite rp2350 firmware (i recommend UF2 Loader release)