Kock-Werner Redoubles
When partner's low level overcall has been doubled, a redouble calls for a take out. For example:
South West North East
1C 1H Dbl. Redbl.
East shows that he has a singleton or void in hearts, and requests a take-out into another suit. The possibility of playing in two clubs is not excluded: the best escape is often to bid a suit bid by the opposition.
Such redoubles are almost useless in a natural sense. If east is satisfied to play in one heart doubled, he simply passes. (This convention needs special consideration if opponents are playing negative doubles).