In corporate governance and structure, the roles of both CEO and president often vary, but to better understand them, this is what the president of a company actually does.

Across the world, many companies have separated the roles of leadership among their ranks. From CEOs to chairman and president, each and everyone can have a specific order to best identify the roles to take on.

According to Investopedia, in general, the chief executive officer (CEO) is considered the highest ranking officer in a company, and the president is second in charge. However, in corporate governance and structure, many permutations can take place, so the roles of both CEO and president may be different, depending on the company. In the corporate world, however, the president often refers to someone who is the leader of a segment or critical part of the overall company, rather than the leader of the overall company. In some instances, the president is also the CEO. In small businesses, the president might also be the owner of the company. According to others the president of a company creates, communicates and implements the organization’s vision, mission and overall direction. He hires, fires and manages all employees of the company.

Sometimes, they’re the CEO’s No. 2. Other times, they’re bundled in with the CEO and chairman positions (you’re probably not surprised to find out that’s Jeff Bezos’s setup at Amazon). And sometimes…the president doesn’t exist at all.

But what does the president actually do?

In a corporate hierarchy, the CEO is the No. 1 official, most powerful in a company, and the President is the No. 2 official in a company. The CEO reports to the board and the president reports to the CEO, but to understand No. 2, let’s start with No. 1, writes daily business newsletter Morning Brew.

The CEO is the highest-ranking exec and the public face of a company, they’re responsible for setting the long-term vision, mission, and strategy. They liaise with the board of directors, make sure the ship is on schedule and course, and pray to the regulatory gods they don’t have to kowtow up to Capitol Hill.

Assuming the president is 1) existent and 2) distinct from the CEO, they generally oversee day-to-day operations, like making sure a new product gets launched on time. In other words, they convert the CEO’s vision into reality. They might be managing the managers, setting objectives for different business units, and lubricating operations. They’re also probably keeping a close eye on the CEO’s back, as both the CEO and the President have a good working relationship with the Board Members despite that the CEO has a permanent seat at the Board, whereas the President may or may not have the seat at the board.

A CEO’s and President’s responsibilities may vary depending on the vision, mission, strategic goals, products and services, according to Sudhakar I. Prabu, business.com writer, but just because a president isn’t top dog doesn’t mean they’re invisible.

The president is the ultimate successor of the CEO. One critical element that can measure the president’s success is their partnership with the CEO, for the trusting partnership between CEO and president, is the most challenging and difficult of all organizational relationships. The president’s success also depends on closing the execution gap and achieving objectives set by the CEO.