I've moved a few apps from my personal account to a client's company account.
Unfortunately Apple won't just move it to the new account; you have to pull the original app from the store before you can re-submit it under the new account. It has to get re-approved all over, even if it's the exact same app. That means it'll be out of the store for a week or two. Plus you lose all the reviews in the App Store, and anyone who bought your original app is kinda screwed - if they want updates they have to buy the new one again.
Not convenient but it mostly works! Of course if you are just upgrading your personal account to a company one it's probably much smoother.
Cheers,
Nick