How to acess control rig variable in blueprint?

Enter_Reality already gave the answer but for more clarity read this:
Control Rig in Blueprints in Unreal Engine | Unreal Engine 5.5 Documentation | Epic Developer Community (epicgames.com)

You can set and get control rig details using the above approach.

Another answer to a similar question: How to add control rig to blueprint class - #7 by alan_void