There's a subset of "The Know It All" segment that we've all had to deal with in business ... this person is "The Bully".
I face this when I play pickleball. There's a bully, and at first it is intimidating to play against the bully. The person hits the ball HARD and pushes you around and makes you play a style that he wants to play. However ... however ... if you push back immediately against this person and set the tone from the first point, the bully backs down.
The Virtual Chief Performance Officer "tests" the bully, right from the get-go.
As a Consultant, you face bullies all the time. In fact, the Consultant is frequently hired because a bully is making life miserable for his/her co-workers, to the point where nothing gets done. I've made a living because of this dynamic.
Assess if the Bully backs down when presented with facts.
Assess if the Bully storms back with theory when presented with facts ... this is the same as backing down. If you present facts and the bully comes back with "WHAT ABOUT THE BRAND, WHAT ABOUT THE BRAND?" in all caps (as happened repeatedly when I worked for a client back in 2008), you have a bully. In marketing, the word "branding" or "brand" is code for dealing with a bully. Branding is not rooted in customer facts, branding is an opinion. When a marketer tells you that the marketer won't do something because it will "hurt the brand", the marketer is being a bully, and is choosing marketing faith over marketing science. The marketing leader just opened the door, and it is your job as the Virtual Chief Performance Officer to drive a ton of customer facts through that door, right now.
Merchants employ comparable techniques, talking about a "trend-right assortment". That's the merchandising version of "branding". It's merchandising faith, and it opens the door for you to drive a dump-truck full of customer facts through the door. Do it.
CEOs will bully you incessantly if you let 'em. They will combine their knowledge of their company with CNBC-fake-facts (i.e. "the industry" is really struggling right now) and Woodside Research reports to triangulate into a position that aligns with his/her worldview. When the bully does this, you have the bully "backing up" ... drive hard to the basket with customer facts.
In general, I've found it counter-productive to deal with the Know-It-All head-on. However, I've found it highly-productive to deal with the bully head-on. Bullies back down in the face of an onslaught of actual, actionable customer data.
Identify if you have a Know-It-All or a Bully.