We just bought a house and several windows have casement hardware
issues.

In the master bedroom, the small round 'gear' that the crank handle is
supposed to attach to is missing.
We have tried to remove the entire operator mechanism without success.
Part of the mechanism is rivited to the bottom of the window and one
screw seems to be located in a location with next to no clearance.

I have two questions:
1. I am willing to 'sacrifice' opening one of the two windows in the
kitchen if I can use its gear. Is it just a matter of unscrewing the
gear with visegrips? I do not want to break the gear in the kitchen
and be stuck with 2 sets of operators that I cannot replace.
2. What is the trick to detaching the rivited operator?

I must admit that I am not very handy and could be using the wrong
teminology.

Thank you in advance for all suggestions.