Vastavam web:Visal Sikka has resigned as managing director and chief executive officer of the company with immediate effect and Praveen Rao is appointed as temporary CEO of the well reputed Indian software company. U B Pravin Rao has been given the interim responsibility for both the posts , India’s second largest software services exporter said in a statement. Sikka has now been appointed as executive vice-chairman, Infosys added. He had just completed three years as the CEO of Infosys. Infosys has been battling both internal and external challenges in terms of uncertain global economic environment and high-profile founders flagging concerns around alleged corporate governance lapses at the company.