You can call it managing sideways.

When David Ellison and Ynon Kreiz, the co-CEOs of the newly-formed media conglomerate that'll be known as Skydance, officially take the reins, the pair stand to make some extraordinarily difficult decisions. They will have to figure out how to integrate Paramount Skydance and Warner Bros. Discovery, apportion resources across movies, television, streaming and news, and decide which leaders and expensive creative bets will shape the combined company's future. 

Having two CEOs could improve those decisions. It could also make them worse.

Obviously, Ellison and Kreiz cannot jointly deliberate over every consequential choice. Any workable business partnership requires clear decision rights. Partners must divide responsibilities, delegate to each other and determine who has the final say when their territories overlap. Otherwise, two leaders become a bottleneck.

Partners do not have to make every call together. But when a decision needs both their perspectives, the successful ones know how to turn private thinking into something both partners can quickly and easily examine.  

I've taught thousands of executives at Harvard Business School, and I often tell my students that what can feel like overcommunication is often the bare minimum for the communication you need to be the most effective. 

A solo leader can leave assumptions, doubts and competing priorities swirling, half-formed, in their head. But you can't do that once you are working with a partner, whether it's a co-CEO, a co-founder or longtime collaborator. 

When you are discussing fraught topics, agree in advance about those decision rights. Who is going to advise and who makes the final call? Or do you both have to be unanimous before you move forward?

If you hammer this out ahead of time, when you question each other's reasoning, it won't feel like you're undermining your partner's authority.

Business partners can and should ask questions like, "Why do you believe that?" "How certain are you?" "What am I missing?" "What aren't we saying?" This is more complex than it may initially seem, because you can't communicate something you haven't recognized in yourself. 

My best advice for how to handle this might seem counterintuitive, but you don't have to wait for your thoughts to be fully clear before you share them. Saying them out loud is the best way to understand them. 

This isn't an invitation to turn the boardroom into a therapy session. But hard numbers only tell part of the story. Your personal investments and hesitations are all relevant pieces of decision-making information, even if you aren't able to articulate them perfectly. 

Perfection isn't the goal here. You can't get a great finished product without the rough draft. So establish with your partner, for example, that "the first 15 minutes of this meeting is going to be the brain dump phase," and then go from there. 

As people become close, they learn each other's consistent personality traits — she is optimistic, he is cautious. But the trouble is that you can mistake that familiarity for access to each other's minds in every moment. 

The result is you assume you know what they're thinking, so you stop asking and learning. Knowing someone's baseline characteristics is not the same as knowing what that person thinks about this decision today.

Trying to imagine another person's perspective does not make us more accurate. This is a sneaky mistake and one of the most common ones business partners make. So make sure you're going into any meeting with a partner with a few questions prepared. If you are not asking any questions, you're likely relying solely on assumptions. 

The newness of Ellison and Kreiz's working relationship could help them here because new partners know they must explain themselves and ask questions. Whether they realize the potential of their partnership remains to be seen, but doing so will require practicing explicit communication from the beginning.

Leslie John is the author of "Revealing: The Underrated Power of Oversharing″ and James E. Burke Professor of Business Administration and Unit Head, Negotiations Organizations, and Markets Unit, Harvard Business School.