Sometimes, it happens. CEO of your Corp goes AWOL and that can jeopardize your operation since a lot of roles and recruitment relies on them.
But if you're in a role of Deputy CEO, starting from Patch 24 you can initiate a takeover if CEO has been offline for over 30 days. All you need to do is press the button in the member area and 48 hr countdown will begin.
During this countdown, a notice will be visible in the Corp window and any other Deputy or CEO themselves would be able to veto it, instantly cancelling the countdown. Unless CEO logged in however, process can be initiated again nearly instantly.
But if it finishes counting to zero, you become the new CEO with all the privileges and access of your precessessor.
It's all up to you now if you can make it work, good luck.