If you can access the neck end of the die, and I know the redding ones are comparatively so complicated, drive a fine screwdriver down between the neck and the sizing bush to sort of kink the case neck away from the bush - it should drift out with a brass drift quite easily once you've removed the tool.
You can buy a new bush if you happen to score it.
A lot folks will poo-poo my next suggestion which is to buy the Lee neck sizing die instead, in my opinion does a better job than the redding one and I have both brands for my 22 savage high power.
I've never broken or jammed a case in a Lee one either and I have them in 22 hi-p, 223, 22-250, 30/30 and 308 - just follow the instructions.
The one and only criticism of Lee's product is if using them to crimp cases with lubed cast boolits seated they can gum up with the mule snot but it's nothing that a periodic cleaning won't cure, or adopt powder coating but that's a whole different story.
Just my $0.02 worth.