Would you want to even if you could? The Glock G20/21 was built on a 10mm frame, it's not a converted .45 to begin like lots of others. It'll handle the hotter ammo fine.
10mm is fine and all, I have a G20 and a G29 and like those just fine (that I may wind up trading/selling when I get around to it, along with mags, dies, lots of brass and bullets and a G29 Milt Sparks rig, just haven't been using 'em really...). But I think a .45 Super would be the way to go for any conversion. Makes a bigger hole with a heavier bullet at similar velocities, and being based on the 10mm frame it's doable.
Not a fan of carrying modified gear though so there's that, and why I haven't done it myself.
Glock 10mm is hard to beat, the goto 10mm IMO/E.
Smith 1006 I had was a TANK but mags were getting hard to come by and starting to get pricey (over $100 on average a year or two back). 9rd. capacity and reliability and weight though made it not ideal for carry. G29 is a bit brickish but still totally carryable IWB, G20 is, well, like carrying a G21 I guess --fine in an OWB rig. 15rds, reliability and ruggedness/ability to handle high power loads made it top the list if you ask me.