strongMumbai:/strong Ratan Tata, who led the transformation of the Tata group from a conventional corporate house into a $100 billion global conglomerate with high-profile acquisitions abroad, will retire tomorrow ending a 50-year run in one of India's oldest business empires. Marking a generational change, Tata, who turns 75 on Friday, will hand over the reins of the group to 44-year-old Cyrus Mistry, who was chosen his successor last year and formally appointed chairman earlier this month.[caption id=attachment_570498 align=alignleft width=380