The phrase "complete overhaul" means making extensive changes or improvements to something, often by replacing or repairing all of its parts. Full definition
The awards, totaling $ 107 million over five years, all but complete an overhaul of the department's often - criticized research operations that began in 1994. (edweek.org)
Simply put, the visuals are superb but the audio could use an almost complete overhaul. (videochums.com)
But village officials decided it needed a more complete overhaul after realizing that the large amount of information it had made it increasingly difficult to navigate. (articles.chicagotribune.com)