DUESSELDORF (Reuters) - Thyssenkrupp’s steel unit, which Britain’s Liberty Steel wants to buy, has cut reliance on shortened working hours, a spokesman said on Thursday, adding that alone was not yet a sign of a sustainable demand recovery. “The economic collapse caused by corona is not over yet, even though some markets show signs of recovery. How sustainable these trends are is currently unforeseeable,” the spokesman said. Thyssenkrupp, Europe’s second-largest steelmaker, continues to rely on the instrument of shortened working hours but could reduce it by about a quarter compared to the summer months, he added. The group will review the situation by the end of the year to decide whether it will still need short-time work in 2021.