Moving bones without moving IK

Hello,

here’s the situation:

I have a model with human-like bones. There is an arm bone, a forearm bone, but also an IK bone “connected” to arm and foremarm.
Everything works fine, but at some point in animation I want to move just forearm, without moving arm bone. And here’s the problem. Because of IK I can’t do it without moving IK. Trying to position IK so it looks like arm stays in place is a fool’s work.

So thats my question:
Is it some workaround for this problem? Like ignoring IK at some point or smth?

Kind regards.