Users should click "Start over" or "Go back" button when they want to start over or correct the mistake. Logo has nothing to do with that. Logo as a link to homepage is an established pattern you do not want to break.
I think that, to understand whether it should be global or micro-site homepage, you have to answer the question if users perceive the website as separate property or not. Thing MSN Sports and MSN Money vs. 2 different departments at Amazon.
Implementation may vary. Take this very website as an example. Smaller "StackExchange" logo leads to global website, and since this is is probably the only logo people notice, they were forced to add confirmation flyout. And I'm pretty sure that people struggle to notice bigger UX logo, because it is not sticky and because it is in funny place.
Already mentioned MSN indicated that you about to navigate globally but it still created a little bit of unease, because user can still not understand how to navigate to local (property) home.
In some cases, e.g. Amazon checkout flow logo is not functional because they want you so stay in the flow by any cost. The only way you can stop the process is to close the tab, in my opinion it is annoying and not nice. But this flows usually have plenty of ways to correct a mistake.
I personally prefer MS approach to use product name for "go home" and waffle menu for global nav.