I subscribe to a number of services that look for pithy quotes from Big Names, authors, and other people who are looking for publicity. I saw one about moving from manager to leader.
Ok, so these are writers or reporters, and they may not know. Choosing to be a manager without being a leader is like choosing to drive across the country without a map. Choosing to be a leader without having management skills is like choosing to be a fish without gills. You have to know where you're going, and you have to know how to breathe in your environment.
Managers set the strategy and the vision, so everyone knows what is going on and can work on the most important work. Managers create the environment so that the people all over the organization can succeed, including the managers. They are not the only people who do this, but they are the leaders who must do this. If managers do these things in a command-and-control way, they might succeed. If they choose servant leadership, they are more likely to be successful.
Managers must be leaders. We cannot choose between management and leadership. We must have both.