Reply to loop knobs getting stuck

hi people in the community
i was just looking for advice on what i can do to the right loop size knob on my kontrol s4. recently it become stiff to turn and gets stuck when pressed down. i found that if i wiggle it around a little it helps loosen it up but only for a short while. im not sure if theres a way to remove and clean it or whether this can be replaced.

any ideas would be appreciated