Redenomination under hyperinflation doesn't save the suffering economies. What it does is make it practical to pay for goods with cash, at least for awhile.
When hyperinflation is involved, redenomination becomes necessary because it requires too many old notes to facilitate commerce effectively. For example, in Zimbabwe, the small bills formerly available become essentially useless if it requires a truckload of them to buy a loaf of bread which may cost five million Zimbabwe dollars.
In 2009, a third redenomination occurred, with one trillion ZWR being exchanged for one dollar of the new currency (ZWL). Despite the multiple redenominations, the inflation continued and ZWL continued to lose its buying power. By 2009 the U.S. dollar was the primary currency used in the country, and the Zimbabwe dollar mostly stopped circulating.
In 2015, the country began the process of abandoning the ZWL altogether and instead just using the U.S. dollar.