Question about Sony WH-1000XM4

Most likely, either as an accessory or from Sony's after-sales service, as it's a wear-and-tear item for high-end headphones. Note that the current price is rather low-end while stocks last, so think fast if you want to benefit from high-end sound and performance at a stock clearance price...

They are not glued but fastened with a plastic hook. So a change is possible but not quite as easy. There are instructions and videos on the internet. For example from Sony: https://www.sony.de/electronic...
Earpads not from Sony e.g. Dekoni Audio Earpads (Sony WH-1000XM4)